Living in the arid west, I feel every car should come with intermittent wipers as a standard feature. Unlike the Mid-west, where rain comes in two forms (wet and even more wet), the states anchoring the southwestern corner of country almost never see normal rain. Instead, we see “just a little drizzle,” or “so much damn water you really ought to park the car.”
Because of this, I planned to add intermittent wipers to the El Kylemino, but was not very familiar with GM wiper systems. To address this gap, I started a research project to see what it took to convert standard GM wipers to intermittent. The web gave me lots of information up front, but half of it conflicted with the other half. In addition, I encountered odd phrases such as “depressed park,” “pulse board,” and “pulse relay.” Clearly, I needed to build my understanding of GM wiper systems before I could convert my car to the desired system.
Today, I’ll share this research with you, and explain how GM wiper systems evolved into the system used on the 5th generation El Camino. Next time, we’ll start all over because of a major change GM made to the wipers in 1984 (those bastards!).
The story behind this week’s wiper system goes back to 1968, when the engineers at GM developed a hidden wiper system for many of their models. By building a well in to the cowl of the vehicle, and then cantilevering the back of the hood over this space, they created a “cave” to hide the wiper arms when not in use. To park the wipers in this space, the engineers built a new wiper motor and transmission designed to retract the wiper arms below the base of the windshield.
If that sounds a bit complicated, you’re right. In order to make everything work, the designers created a unique control circuit using a “park relay.” During operation, the wipers move up from the park position prior to sweeping the glass, and then retract after of the final sweep. Adding to the complexity, the engineers also used a “switch to ground” circuit, which means the control switch is on the ground side of the circuit, instead of the power side.
To add to the confusion, on certain lower priced name plates (think Chevy), GM chose to offer the hidden wiper feature as an extra cost option. That meant the factory had to keep track of different switches and motors used during assembly, since the parts are not interchangeable between the two systems. In fact, the second generation Camaro parts book shows 10 different wiper switches. However, by 1975 GM made hidden wipers standard on most of their cars supporting the feature, including the El Camino.
As a final piece of the puzzle, on many GM wiper motors, the gear box also ran piston style washer pump driven by the wiper motor. To use the pump, a solenoid in the motor cover engages a four lobe cam that drives the pump piston. Of course, the El Camino also used this feature.
In 1974, GM added an option called the “pulse wiper,” a feature most people call intermittent wipers. Rather than redesigning the system, they adapted the existing parts to work as intermittent wipers. During operation, the wiper blade paused at the end of each sweep, and remained on the glass until the next intermittent sweep. The arms only moved to the depressed park position when the driver turned off the wipers.
To keep things simple, GM designed the pulse wiper system to piggy back on the existing motor. The cover containing the wiper motor became a “pulse cover” and now included a circuit board with an additional terminal for a new signal wire. GM also cut the motor power wire in two and added a pair of terminals so the wire could connect to a “pulse relay” inside the pulse cover.
The fifth generation El Camino used this system when it was released in 1979, but GM wasn’t done making changes. In 1982, they moved the wiper switch from the face of the dash to the base of the turn signal switch in the steering column. With this change, you now had to pull the steering wheel and remove the turn signal assembly to get to the wiper switch.
So as you can see, there are many variations to GM wipers over these years. Technicians working on GM wipers needed to determine if the car was equipped with standard wipers, depressed park wipers, or depressed park wipers with pulse (intermittent) wipers. In addition, they needed to determine if the wiper motor cover included a washer pump (not every depressed park system did). But at this point, I was confident I had identified every possible GM depressed wiper system variation.
Based on this information, I built the list of parts required to install intermittent wipers in the El Kylemino:
- A new wiper switch in the steering column.
- An additional wire from the switch to the motor (unless GM included the wire in every harness).
- A motor pulse board (including a washer pump).
- A new wiper motor (if I could not modify the existing power wire to work with the pulse board).
However, before I started the project, I discovered the source of that conflicting information I mentioned at the top of the post- In 1984 GM tossed EVERYTHING out and developed a completely new system with an entirely different motor, pulse board, and circuit design. Time for some more research…
More on GM wipers:
Part 3 (coming soon)
Having had lots of experience with these wiper motors, and knowing how engineering companies work I would suggest that post 1968 GM just kept jury rigging features onto their existing design because that was expedient, backing themselves into a corner of rube goldberg-ness.
That was the classic 70’s or early 80’s GM car experience, touch the washer button once, the solenoid would engage the cam and:
BOOSHKA BOOSHKA BOOSHKA BOOSHKA
About 10 times as much fluid as you needed would be deposited on the windshield. And if it was a slushy day or a light rain, you would soon run out.
“BOOSHKA BOOSHKA BOOSHKA BOOSHKA”
That “we already know how dirty your windshield is before you do” system was an old one, as it was on my 63 Cadillac too. That may have actually been my first actual repair, fixing something in that washer mechanism to make the washers work. And yes, something like ten squirts every time. Which is a pain in diagnosis because you know if it’s not working after the first squirt attempt.
On my 78 Malibu classic with intermittent wipers , if I pressed the wash it would not stop washing until I pulled the fuse . I replaced the switch on the dashboard but it didn’t fix it
I never figured it out so I avoided using the wash ,just used it when my windshield was salt covered
The wipers worked on al! speeds worked intermittently and parked with no problem ,just the wash
I don’t know how it relates to the GM way, but at least some Chryslers with depressed wipers used a motor-reversal system. On turn-off, the polarity of the power to the DC motor was reversed, the motor would turn backwards, and a grease-damped rotary clutch would slip; the linkage was designed so that this would cause it to lengthen and park the wipers in the depressed position, at which point the power was cut off. If the grease dried out and hardened, the wipers would sweep between the depressed position and a not-complete upward limit. If a spring inside got weak and the grease was otherwise OK, the linkage would lengthen and shorten during the normal wipe action, causing interesting visual entertainment and a lot of noise. The Chrysler depressed-park wipers I had to deal with went away with the last of the fuselage cars, the 1978 B-body sedans, though they did carry over to the 1969-1971 R-bodies. My current Chryslers don’t have it.
Vacuum wipers were innately intermittent and rain-sensing. When you turned the knob about halfway, the wipers would move only when the windshield was wet enough to break static friction. They’d make a couple wipes until it was dry, then pause. “Soft power” has its advantages.
Vacuum wipers were especially intermittent when you accelerated or went uphill. In rural flatlands this was tolerable, but in hilly San Francisco, NOT!
My 1961 Ford had vacuum wipers; wide open throttle (necessary to keep from getting run over) would bring the wipers to a halt. On the other hand at idle the wipers would go back and forth at a high rate of speed.
As a little kid in pretty the fairly flatish Buffalo New York area I remember the wipers on the family 1950 Studebaker. They would halt or close to it and then flip back and forth about ten times faster than later cars with wipers on high. Just accelerating through the three gears would cause this with the hysterical flapping at each shift and slowing or stopping with acceleration in each gear. It was a Champion so probably full speed ahead was necessary in each gear. The replacement 1956 Plymouth had two speed (I think) electric wipers. I have no idea who ever thought vacuum wipers were a good idea.
I guess there could have been a vacuum tank to smooth things out, but no.
I think that vacuum wipers were common on AMC cars after they had largely or all disappeared from others.
I would like to go back in time to when some car designer decided it was an embarrassment for the windshield wipers to be seen when not in use. Then I want to throttle that guy, because the solution that was created added needless complexity solely for the purpose of “style”.
The modern solution is much better – just paint the darn things black!
This was also about the time GM came up with the infamous radio antenna embedded into the windshield. Besides generally not being nearly as good as the old-fashioned antenna aerial, it also had the unfortunate tendancy of going in and out as the wipers went over the windshield.
And then there was the side-terminal battery. GM was chock-full of innovative, but not very well-executed ideas at the time.
Answers to problems nobody had? But then along came all the government legislation and regulation and they really had their work cut out!
And the wiper cavity would pack with snow in the winter…if the wipers stuck, the circuit breaker would trip….PRESTO, no wipers for a while until it reset. It gave you time to dig them out.
“And the wiper cavity would pack with snow in the winter”
Bingo! And you couldn’t leave them halfway up because when you would start the car to get the heat going the frozen wipers would labor mid-cycle until they broke free or blew the breaker. Gad but I hated those things.
I daily-ed a ’79 Caprice Classic in New England in the 80s.
Step 1: Park car and kill ignition with wipers running and as close to vertical as possible
Step 2: Go inside; get into frigid bed; wake up to frigid, terrible darkness and go back outside
Step 3: Sweep windshield
Step 4: Excavate ‘wiper cave’
Step 5: Bang wipers with fist, breaking them free from icy windshield
Step 6: Lift and drop wipers repeatedly, breaking the coating of ice that entombs them.
Step 7: Fall heavily on ice-rutted pavement
Step 8: Get in car and, eventually, manage to start it.
Step 9: Shiver violently; fumble with gloved hands to turn off the frozen wipers as they skitter uselessly against the glass.
Step 10: Wait for car to get warm enough/defrosted enough to drive.
Step 11: Turn on wipers; BOOSHKA BOOSHKA BOOSHKA BOOSHKA until windshield is clear.
Step 12: Get stuck in driveway; go back inside and drink until spring.
This is a GM-centric examination of windshield wiper operation, but I wonder if the story of that guy who supposedly invented a workable version of intermittent wipers that Ford subsequently ripped-off warrants a mention.
Robert Kearns eventually got his compensation but it cost him his famity
I always wondered why it took GM & Chrysler 8 years to reverse engineer the interval wiper.
I forget when GM got them but Chrysler didn’t until 1978
” I wonder if the story of that guy who supposedly invented a workable version of intermittent wipers that Ford subsequently ripped-off warrants a mention.”
I was aware of the trials and tribulations of Robert Kearns, but wanted to focus on the evolution of the system design.
“I forget when GM got them but Chrysler didn’t until 1978.”
I first found a GM reference for them for the ’74 model year (on a Cadillac), but that’s not definitive…
As the attached file indicates, AMC offered them as early as 1972. Their wipers did not have a depressed park feature, so it was simpler to add the feature. Also, based on the design of their dash switch, I’m confident they bought the components from Ford.
Talk about over engineering…and I must commend you on your research.The Ford system like on my Ranger are much simpler. And with vacuum wipers, it always seemed to rain the hardest when going uphill…
Yeah I’ve converted some of my Fords and it is a matter of unplugging the harness from the old switch, plugging that into the delay box, replacing the switch and plugging the other wire from the control box into it. I also used a Ford Box to create a hidden intermittent system on my Scout that uses the OE switch with the small potentiometer knob for delay hidden on the bottom of the dash where you don’t see it if you are not looking for it.
The Fox body/Ranger systems don’t have the depressed park option, which makes things MUCH simpler. I know the GM square body trucks also used the “Plug in” approach, and I’d assume the H-bodies and the like were similar.
Isn’t the corporate name-of-the-game…profit?
What if GM had simply designed a new intermittent wiper system way back when, and made it standard equipment? I think what they’d have perceived as an extra-cost luxury back then, would in the long run have been more profitable, all due to factors beyond the cost to make the wiper motor itself.
In Aaron Severson’s excellent history of the 1967 Impala, we read that 150,000 possible production variations existed for the ’67 model (I’m assuming full-size line here)…that’s before special orders such as COPOs and the like.
These variations drove up costs and compromised assembly quality. Both of which hurt profits – one sooner, one later.
Hence, over time, the appearance of such amenities as power windows/locks, etc., and indeed, intermittent wipers, on base models today.
Yes, there’s the bugaboo of having to buy option A to get option B – because they’re all part of an option package instead of the ala carte way like long ago. But buying the package arguably saves $$ for the consumer and drives profits for the manufacturer.
My old ’89 Caprice ran for over 300k miles. (130,000 of those miles with a 350 TPI engine!) So I replaced that pulse multiplex wiper motor a couple of times. IIRC you bought the wiper motor and then if you had the intermittent option, you reused the pulse multiplex board off the old motor. Then you had to line everything up…fun times.
My wiper motor sure looked like the “depressed wiper motor” depicted above. It sure wasn’t the smaller one you show as having begun in 1984…they must’ve stuck with the older technology in the B-bodies for awhile.
The way they do stuff today isn’t as bad as we’re tempted to think.
A few years ago, my neighbor bought an ’02 F-150 base model and wanted to add the factory driving lights. Sho’nuff, the harnesses were there, tucked away and capped off. Just add the light units, change the switch on the dash, plug the lights in and voila!
I learned a costly lesson a few years back when replacing struts on my wife’s 2011 Equinox.
I went and bought the struts. JUST the struts.
But by the time you factor in the labor to remove the pieces from the old strut that need to be reused on the new one, plus buy the worn incidentals such as anti-squeak pads and rubber boots and install those and then compress the spring to remove and compress it again to install and so on and so on and scooby dooby dooby…well, I learned they don’t call the more-expensive complete sets OUICK STRUTS for nothing.
Three bolts at the top, two at the bottom. Simple.
As our CCs become more complicated in many ways, things like quick struts, and one wiper motor across all models, are little ways where it’s actually getting simpler.
Hopefully that 1984 revision on your Elco wipers made things simpler too.
It was Toyota where the domestics learned the trick of offering packages instead of individual options to lower costs and maximize profits. The problem was Toyota was much more adept at offering extra standard equipment and options packaged in a way that customers didn’t feel nearly as much like they were getting screwed as the domestics.
One of my favorites was how, very early on, Japanese vehicles came with an electric rear window defroster as standard equipment. With the domestics, you had to pay extra for what soon became a must-have option. Eventually, the domestics offered the rear defroster as standard, too, but not before they made a nice chunk of change charging for it.
And then there’s the Honda way. Hondas only offer a few trim lines with zero options. They then supply OEM kits to their dealers for a la cart options. A/C used to be a big one. And, man, did dealers rake in the profits on those kits. Seems like the aforementioned A/C used to be around $1200 when a factory installed A/C option on a domestic was little more than half that. But at least you got the factory warranty with a dealer-installed, Honda-branded kit.
No the real creation of packages was done inadvertently by Chrysler and their sales bank, building on International’s quick delivery Prototype system. Both developed due to the fact that JIT production sometimes meant no or little product for the line that day.
With International because they were trucks, they created Prototypes built for a particular vocation. They then had a few options that could be added at the Truck Sales Processing Center. Since they were for work some customers couldn’t/didn’t want to wait. So a quick call meant that a dealer could have a truck on the next train, or ready for a drive-away the next day, before an order could even make it to the plant.
But the biggest change was Chrysler. When the energy crisis hit they saw orders for some of their cars to drop like a rock. Not wanting to shut the line down they told their sales office reps to give them orders, even if there wasn’t an order from a dealer for that car. So they looked at what had sold in their area and started placing orders with the most popular equipment combinations for their area. So 5 in Green, 10 in Blue, 5 in Red with the V8 and AT 8 in white with the 6cyl and 3sp, 6 in Gold with the big V8 AT and AC ect.
Then of course he was tasked with getting dealers to take those cars and to do so they had to give them a reason, and that was price. In addition it was the rebate to get the customer to take some of those vehicles from dealer stock and getting the vaintiy mirror and vinyl top they didn’t really want to save money and drive home today rather than pay more to wait 6 weeks for the car they really wanted.
Next thing you knew Olds had dropped the Can We Build One For You? and replaced it with We’ve Built One For You.
The sales bank was originally conceived as a way to make production more efficient by smoothing out the peaks and valleys of production which resulted in overtime when it was busy and layoffs (with nearly full pay) when things were slow. Great theory. Build popular cars in slack times, have lots of ready inventory when things pick up.
But we were talking about Chrysler in the 70s, so the execution was totally fouled up. All of the pressure on sales and production people was on maintaining volume, so once inventories started getting overfull they – – – kept on pushing cars out the door. Then fire sale prices to the dealers, and the origination of the rebate.
It’s ironic how one of the few management tools from the old Chrysler Corp., the Sales Bank, if done properly, could have went a long way to keeping the company in better shape. In fact, one of the first things Iacocca did when he became CEO was to ‘cancel’ the Sales Bank. I vividly recall in his first book saying how dumb it was.
I can only guess that the normal way dealers ordered for stock was to simply load up vehicles with the highest profit options, and not the most ‘popular’ options. If the company had done the necessary analysis of option popularity, maybe they’d have sold more cars. Instead, it was just a hodge-podge of cars built with whatever option parts happened to be around on a given day, then they were shipped off to a holding lot to wait and hope that dealers would buy them sooner rather than later.
Unfortunately, dealers were a lot smarter and greedier than that. They simply waited until Chrysler was desperate to get the cars moving and discounted them steeply, so the dealers were able to buy them at fire-sale prices.
In effect, it was the dealer network that screwed-up a good idea, i.e., the Sales Bank. It’s too bad Iacocca didn’t see it for what it was and made it work.
The reason they had so many permutations back in the day was to generate profits. The money wasn’t in the vehicle, it was in all the options that could be sold alacarte.
For example color. When you are cranking out a million copies of something it doesn’t really cost any more to source a few thousand yards of different colors of fabric or carpet instead of several thousand yards of one color. And interior color and trim level were a huge part of the possible permutations available.
Once that fabric got to the plant, thanks to the Just-In-Time production used at the time it didn’t make a difference if the seamstress sewed up a red and black, red and white, blue and white ect.
Then you get down to the real money makers, things like charging you extra for an optional gear ratio, or upping the displacement from 283 to 327, that had zero additional cost to produce, but brought in pure profit.
Its a similar story for things like the different grilles, taillights and side trim you’d see between the Biscayne, Bel-Air, Impala, Caprice. The volume was there that if you tried to do it all on one set of tooling it would wear out before the year was done, or you couldn’t produce it quick enough on a single set. The cost difference to make the different dies or molds were essentially nil, since they were largely hand done at the time, before the time of CNC machinery.
So yeah by making the guy pay extra for all the bells and whistles on top of the Impala trim, they could make twice as much money as they did on that Biscayne that went out the door with nothing more than the V8 and automatic.
With the switch from Can We Build One For You? To We’ve Built One For You that did start to change. Now there was a risk associated with excessive variation and the number of choices started to dwindle. Increasing segmentation spreading out sales also mean that it could be cost effective to have one set of tooling, only buy 4 types of fabric instead of 8 ect.
Now of course with so many options being electronic a single harness does work better on the modern assembly line, instead of having overlay harness for certain options, that cause a variation in time at a station.
“It sure wasn’t the smaller one you show as having begun in 1984…they must’ve stuck with the older technology in the B-bodies for awhile.”
That’s correct- Some of the full sized models used the older wiper system through 1990.
The wipers on the GMC motorhome were powered hydraulically from the power steering pump.
As were the ones on dad’s ’64 Lincoln Continental.
Hidden Wipers were introduced on the 1967 Pontiac “B” bodies, Bonneville, Grand Prix, Executive, and Catalina. The hidden radio antenna (embedded) was also introduced by Pontiac for the 1969 Grand Prix. The unfortunate thing is; being old enough to remember both the advertising for the feature and the buzz it created and one of the neighbors purchased the car and “showed-it-off” to the neighbors. (Is that still a thing?)
My first car was a 1967 Pontiac Catalina with the recessed park wipers and they were a pain. Snow packed cowl, freezing rain or drizzle, and the girlfriend’s tendency to leave the wipers on when the engine was shut off, leaving the wipers where-ever on the windshield, invariably in freezing weather; caused many a tripped breaker or dropped center pivot of the wiper arm transmission.
Another great feature was when parked, the wipers dragged across the bottom of the windshield and rested on a piece of stainless steel. This insured that the wipers received new refills at least twice a year. Also great was during snow falls or snowstorms, the cowl would become packed with snow so that the wipers couldn’t park, so the motor wouldn’t complete it’s cycle so it wouldn’t shut off. See breaker and center pivot comments above!
My father always marveled that I had replaced so many wiper motors and wiper transmissions in the three years of ownership – always stating that in all his years of car ownership, he’d never replaced a wiper transmission.
All this being said, it was my first car and I’d dearly love to have another ones. Now, if only I could lose 70 pounds, regrow my hair, and lose those 45 intervening years, I’d have it made.
Questions I have about wiper systems –
I cannot recall a European car build after about 1972 with wipers controlled by a dash switch not a column stalk, but when did this format become common or universal in the US?
Wouldn’t a simpler solution to the intermittent option have been to install common motors and control boards to all vehicles, but omit the intermittent position on the switch?
Why are washer jets adjustable (except on Alfa Romeos)?
“Wouldn’t a simpler solution to the intermittent option have been to install common motors and control boards to all vehicles, but omit the intermittent position on the switch?
As you’ll see, the system on my ’87 takes that approach, except of course, GM kept modifying the pieces as time moved along.
My 2002 Porsche 996 had the wipers on a stall but the intermittent speed variability was controlled by a knob on the dash.
Well in the early days they were adding it on to existing systems, but Ford at least, as mentioned above had a box that fit between the switch and motor if you have intermittent and on some the basic switch was the same w/o the contacts/position for intermittent.
The European-style stalk controls became commonplace in the early 80s, though some of the older models maintained the old dash switches.
I believe GM moved the switch to the turn signal stalk starting with the X-cars. Then it expanded to the rest of the lineup in ’82.
A few things I remember about these “depressed” wipers. In my ’79 Grand Prix, without intermittent, when you turned them off they would loudly CLUNK back down into the well. We also had a ’79 Cadillac which did have the pulse feature and when the wipers would complete a stroke, they would always move up slightly to rest before waiting for the next stroke. So it was like three motions to each sweep – up-down-up just a bit. Sort of weird to watch.
Here’s some real GM fun for you: my Cutlass Ciera wagon has the wipers which park like they were hidden, but don’t actually hide.
So complicated, my old car has two speed wipers on and off no self park nothing I was going to upgrade but the windscreen seal leaks so I dont use it in the rain,
My Citroen has a mind of its own where wipers are concerned literally thats the first click of the stalk termed auto wipe active on the info screen, it works quite well and the wipers do pass over the sensor after that it has two set speeds,
DAF trucks have a handy intermittant system switch the wipers on then stop them just before they complete a sweep the restart them when required and thats the inermittent setting, infinitely adjustable, I like it.
As a patent attorney, I appreciate your including the abstract – “means” is avoided these days so it made me smile!
I just replaced the washer pump on my 68 Caprice (with depressed wipers), so those pics also are familiar to me! I had to remove the wipers to reset them on their shafts – when the car was repainted and other work done the wipers didn’t depress. Instead they stayed visible like on a caveman’s car! Unacceptable! Now they disappear as nature intended. Of course now wipers are visible again on almost every vehicle. I wonder if the aerodynamic penalty is worth not depressing them behind a higher hood/cowl.
As JB mentioned above, true hidden wipers like the ones GM had throught the ‘70s are now rare, but there are a number of new vehicles that have sort of a hybrid hidden-but-not-quite hidden system, where the wipers park in a well between the edge of the hood and the windshield. I guess that is a compromise; the wipers are concealed unless you’re looking down at the cowl, and at the same time it allows the wipers to be flipped away from the windshield when the weather is icy or snowy (or both).
I learned to drive in and around Baton Rouge and New Orleans, where it snows lightly about every 10 to 15 years, and even before I moved northward I was amazed that a Detroit-based manufacturer would have a design that would fail to function in winter weather.
“I feel every car should come with intermittent wipers as a standard feature.” Me too. So back in the late-80s I bought a J.C. Whitney intermittent wiper controller for my ’78 Malibu, wagon, installed it and never got it working. Sure wish I had this article back then.
Anyone else hate those flimsy dangerous gm multifunction switches? They felt flimsy and the cruise resume button was easy to hit and took next to no effort to engage by accidents as you turned on the turn signal as you slowed down for a turn. Then halfway through the turn resume would engage and it it was wet or snow and ice it was easy to lose control. My olds Delta 88 had that. If you hit resume when putting on turn signal about 5 seconds as you turned later the cruise would engage and the 350 would shoot forward at like 3/4 throttle. Plus they were fameous for failing when driving at night with the high beams on they would be fine then there would be a puff of smoke out the steering column then the headlights would go out as you slam on the brakes and try to remember where the road is. The Ford competition was way better with seperate switch though on the steering column and cruise on the wheel where God intended it to be.
GM has slowly learned, my son’s 2003 Buick has wet arm wipers like a truck (washer nozzles on the wiper instead of the hood) which give better coverage, also they gave up on hidden wipers.
Mercedes-Benz has some of the most interesting wipers, with outward pivoting “clap hands” wipers in the 60s and early 70s and the unique single “jumping” wiper on some 80s models which followed an eccentric path.