As usual, the day after I published my ’62 Plymouth & Dodge article I woke up early and started thinking of numerous details and connections that I left out, never mind just some polishing and editing. So it’s going to be a work in progress. One of the details I forgot was to show you properly was just how fine the speedometer in the ’62 Plymouth was; the best of the whole era (and then some) and very C2 Corvette-worthy. And of course, it went away in the ’64 redo.
I’m cheating a little bit, since this is a ’65 Dodge Coronet dash, so familiar to me. And ever so dull and uninspired. And these horizontal speedometers were so non-linear, and hard to read, as the the numbers were most compressed right in the range where the speed limits were. What a let down.
Admittedly, the ’64-’65 Plymouth dash still had round instruments, but symmetrically placed and the speedometer was now the same small size as the others.
Like I said at the ACD museum meetup, these cars have such wonderful parts on them, but the overall effect is so ugly.
Which is why they are so awesome!
To my eye the overall effect in the Plymouth is beautiful. Which is why it’s so awesome!
Gonna be honest-I’m a sucker for a good IP shot. I like the clean font. Strictly business, no frippery there. It’s always weird to me, though, to see gauges without the secondary speed markings.
I wonder if it’s a function of growing up after most of the linear speedometers had gone, but I think they look neat. I kinda lament that every single neat thing we’ve tried with instrumentation has been abandoned in favor of round gauges. Digital? Gone. Horizontal? Gone. Interesting cut-out with needle behind? Gone. Cut-out with a white disk behind that “fills” the gauge? Gone. Thermometer-type? Gone. Drum with numbers that rotates behind a fixed indication line? Gone. Yeah, round are easy to read, but some of the oddball designs were kinda neat. This one at least has some personality, some “essence” to it.
I also have to chuckle at the individual ticks for every mile per hour. I’ve never seen a cable-driven speedometer that held a constant reading, so I imagine those individual ticks are kinda pointless in reality. I mean, even the last of the cable-driven ones in the ’80s floated at least 1 mph when they were new. The (linear) one in our Continental floats about 5. The round one in the Thunderbird floats 1-2.
I think execution rules above all else, and round gauges are simply harder to execute badly. Everyone in favor of round will cite quick glances at the gauge being easier to process, and they are right, but the reality is once you’re used to a car you’ll eventually know pretty close to how fast you’re going without ever looking at it – I can tell if I’m going ten mph too slow or fast – so the speedo can actually be a decorative accessory of dubious ergonomic qualities, which you also get used to with any car you own.
For every interesting example you mention though there were a lot of nasty executions, especially with horizontal strip and digital. Maybe 1/10 cars using them got it right, but most of the blame/credit goes to everything AROUND the gauges.
If you want readable execution, I’d say it’s hard to beat the Chevy Sonic, but I’m not sure that it suits the decorative accessory part. Digital number for speed which you can read without looking directly accompanied by a big analog tach that allows you to see the important motion and whether it’s nearing the red. From an ergonomic standpoint, it’s so good I can hardly believe they made it. I wonder if 50 years will be as kind to it as I.
The gauges in my Honda Civic are like that… a digital speed readout surrounded by the tachometer. I kinda like it….
Here’s a better (clearer) shot zommed in on just the tach/speedo. Like Matt says above, you get used to whatever you’re driving after a while. I too found this arrangement a little strange when I first got the car…
The two Civics before that one did it even better. The digital speed is up at the top practically a HUD and the tach is in the lower peripheral vision. The Insight had it, too and the S2000 helped set that mould, too.
I still like this the best… my 2007 Mustang with its retro 1967 style gauges, right down to the font. What I like best about them? You get the “Big Six” to borrow an aviation term. Our featured Plymouth is awesome, but one of the Big Six seems to be missing. I don’t see a tach in Paul’s picture.
Of course I have to agree with you. I love the setup on my ’09. I also once owned a ’67 and liked the round one on that car. My ’66 has the round speedo also. Good call.
I too like the strip speedometers. The one in the Coronet pictured does look a little cramped, but GM did them better. Nothing like flooring it and looking down at the needle whipping across!
xequar,
To the “gone” list…
Adjustable viewing angle speedometer, an illusion, with the driver in fact seeing/adjusting a mirror which is reflecting the actual speedometer, which is fixed… “gone”
The ’62 Plymouth appears to have both an oil pressure gauge and an idiot light. Didn’t they usually have only one or the other? A light for the lesser models and optional gauge for the deluxe or sport models? I do recall that Chrysler products kept the amp gauge long after everyone else went to a warning light.
I think the oil pressure gauge is a modern retrofit.
Do you mean it was taken from another ’62 Plymouth to replace the clock? Brochure lists the clock as an option, the oil gauge was standard.
An oil pressure gauge was not available on the ’62 Plymouth, not even as an aftermarket accessory. Here’s a pic of the Plymouth IP exploded view in the ’62 Chrysler Corp FPC. Note the clock was supplied to, not by, Chrysler. The subsequent parts listings give part numbers for the ammeter, engine temp gauge, fuel gauge, and oil pressure warning light components, but no oil pressure gauge or associated parts on any ’62s except Chryslers and Imperials. The lack of that gauge shows up fairly frequently as a gripe in road tests of the ’62 Plymouth.
As for the oil gauge shown in the photo: Not a factory piece; it was probably done by one of several speciality houses like Redline Gauge Works or Williamson’s Instruments. An added clue to that effect is the details on the “Alternator” gauge in this picture. That was originally an ammeter; its needle would’ve rested dead centre and its scale would’ve been marked “D” at the left and “C” at the right. Now its scale is “8” at left and “16” at right, and the needle rests off the scale to the left—it’s been converted to a voltmeter, which is another service those speciality houses offer. They’ve also added numerical calibrations to the engine temperature gauge, which originally just had “C” and “H”.
(The car in the picture also has a non-stock, probably aftermarket tilt steering column and a non-stock steering wheel)
Strangely, there’s no mention of an oil gauge in the 1962 owner’s manual. Just the clock in that position, which is listed as optional. A minor mystery…
I don’t think they offered an oil pressure gauge, except maybe as an aftermarket accessory. I think PNs picture is a restoration, and so many of these cars have been turned into restomod Max Wedge tributes that I don’t trust the picture. (Edit – the steering wheel is modern, as is the stitched dash pad.) I suspect that a car without the clock just got a dummy plate as shown here, on what purports to be a restored stock cluster.
The only early 60s Mopars I ever saw with gauges for oil pressure were Imperials.
Remarkable what a good match the oil gauge is to the others in Paul’s picture. Either it’s factory somehow or someone went to quite a bit of trouble to make it look factory.
A retrofitted oil gauge’s sender must have replaced the oil light’s sender. Not both a gauge and light as I thought. Too bad, I’ve always wanted both. (In cars with oil anyway 😉 )
A number of vendors sell modern gauges with factory style graphics to fit original bezels. They’ll create and print custom gauge faces with original colors and typefaces on request.
Daniel and Jim have convinced me that Jim was right in the first place, it’s a modern retrofit. Amazing what you can get made nowadays. Hadn’t noticed the “Alternator” gauge in Paul’s picture is a voltmeter, that’s a dead giveaway. I’ve never owned a car with an ammeter, that’s why. Too bad the factory dash didn’t have all four gauges. Thanks guys.
Those Plymouth instruments look better than the later ones but I’m British, and therefore I’ve got a soft spot for classic Smiths instruments
But unlike the gauges on a Jag-you-arrrrr; the ones on the Plymouth actually worked all the time.
🙂
I have really enjoyed all the various articles on the 62 Plymouths and etc. It seems to me that the major takeaway is that Chrysler abandoned their core competencies of engineering and quality construction and started a styling war that they had no hope of winning. While they did well with the first battle, “Forward Look”, the really did not have a decent way to follow up and Ford and GM soon responded and knocked Chrysler down.
One can only imagine what the history of Chrysler (and the entire domestic auto industry) would have been if they had stuck to excellent engineering and quality building and just played follow the leader on styling. A little industrial espionage could have showed that what GM and Ford were really planning and they could have just followed along.
Of all the sad tales of tongue or pen………
This dash is simply the best. Big round speedo, and a full set of round gauges. Googie-style shape too, like the shape below.
Best of all there’s both an oil gauge and a light. A sudden loss of oil pressure (like the filter coming loose, which happened to me) gets immediate attention, maybe soon enough to save the engine.
Yes, that instrument panel is about as Googie as it was possible to get (and it is both beautiful and easy to read). But wasn’t that style getting on a bit by ’62?
Apples to oranges, I know, but compare the Plymouth’s dash with the Porsche 911’s (or 901, as it was called then), which came out in late ’63. Also eminently readable, but non-Googie and thus far lass dated.
Googie was starting to decline by 62, but it wasn’t yet “dead” Of course furniture and architectural trends moved slower than car styling trends, A Googie influenced motel or drive in restaurant may have seemed less dated than a Googie influenced car. Naturally buildings last much longer than cars, So I’m sure that plays a role in perceived “datedness”.
Where was the (optional) clock located on the ’62 Plymouth IP? My 1963 Belvedere was very similar but had only a warning light for oil pressure and the optional clock (which of course didn’t work) was located in the main instrument cluster. I thought that horizontal speedometers were ridiculous when they were common but I miss them now that every vehicle has round gauges.
Looks like the optional clock replaced the oil gauge like in your ’63. This photo is from the ’62 brochure, at Old Car Brochures. Too bad.
Mom & Dad’s ’62 Plymouth had the optional clock that replaced the oil pressure gauge; it died soon after the first year or so (typical for this time period.)
I recall the round, bright red oil pressure light would flicker off and on as the car was cranked over, before starting up and roaring to life.
Perhaps time has dimmed my memory; but I seem to recall the oil pressure warning light illuminating/going out with each separate “NANG NANG NANG NANGGGG” of the Plymouth’s (in)famous “Highland Park Hummingbird” gear reduction starter?
Can anyone confirm/deny this 7 year old’s memory?
The ’62 is a big change from the ’61. Which do CCer’s like better?
I think the ’61 is wonderfully Buck Rogers, but the ’62 makes it look preposterous.
I like both as they match the overall personality of each car. Some IP designs are just so right for the car’s image: The 1977 full size Buick nailed it, The 1959 Cadillac IP OTOH looks like it was designed for another car.
ONCE AGAIN, Paul and I agree!
The instrument panel of Mom & Dad’s ’62 Plymouth is one of my long term favorites; often the IP I sketched when bored in grade/junior high/high school.
My dad had both a 1962 Belvedere and a 1964 Fury. The 64 was the first car I owned.
Best gauges on a “regular” car, ever
I think the 63-64 Chrysler dash gives it a run for its money.
That actually looks similar to the 1965 Mercury and 1966 Mustang instrument clusters.
The problem is most people don’t pay attention to the gauges, let alone on how to read them!!!! ===;-}
Nice effort but I much prefer the ’62 Chrysler Astra-dome panel. Beautiful and practical.
Yes, the ’62 Plymouth had a very fine instrument panel (and its designers had a lot of very thoughtful things to say on the subject in general, in this SAE paper).
For ’63 they damaged its legibility by switching to a hokey cowboy typeface with big block serifs.
Besides the goofy cowboy font, the 1963 panel combined the fuel/temp gauges into a single round binnacle next to the speedometer, but they were laid out in a horizontal, pointer-and-scale arrangement within the round binnacle. It looked very strange next to the round ammeter and clock gauges in their 1962-style size and locations.
I suspect that someone in the instrument panel design team had originally came up with the idea that the medium-sized center binnacle would house an optional tachometer but suspect they couldn’t figure out where to put the other three gauges (there were only two binnacles remaining). If the center binnacle had gotten a tachometer, Chrysler simply wouldn’t have allowed a GM-style cutting of the ammeter gauge for an idiot light. In fact, maybe a warning wouldn’t have worked with Chrysler’s alternator system. It’s one thing to watch the needle drop when the engine was idling. It would be quite another for an idiot light to be flashing at every stoplight.
“~Chrysler simply wouldn’t have allowed a GM-style cutting of the ammeter gauge for an idiot light~”
They should have, because unnecessarily routing practically the vehicle’s entire electrical load up to the instrument panel through inadequate conductors caused lots of hair-pulling gremlin chasing and burned off plenty of vehicles too.
Not really—not until the cars were long past their intended useful life. Is it a potential problem when the car gets old? Sure, but when you drive an old car you wear out parts most drivers never think about. And there are ways of addressing the problem: external ammeter shunts, voltmeter conversion, etc. Chrysler began phasing in external-shunt ammeters (thus no longer routing whole-car current twice through the firewall) in ’71 and the changeover was complete by ’76.
Thank you. I’ve been around the Mopar world for 15 years now, and am still amazed at the number of people who just lose their minds over the ammeters and bulkhead connectors.
Perfectly good engineering at the time, and not really that hard to maintain these days.
Gents, the ammeter circuit was a problem well before the cars became aged. Sure, now that the solution to every common problem is widely shared and a phone swipe away, there’s a well known easy fix – undo Chrysler’s OE engineering. However, before the problem was widely recognized it definitely caused issues, including fire.
As to electrical system monitoring, a voltmeter gives a lot more useful insight than an ammeter. For an example consider today’s heavy vehicles, where system monitoring is critical and its cost would practically be no object, it’s always a voltmeter that’s chosen.
All that said, routing the potential for high currents through the cabin and then getting thrifty with conductors was NOT good engineering. As built, the Chrysler ammeter circuit was a poor design, that’s why today even with exacting restorations it’s routinely retrofitted.
I’m sorry to be argumentative, but I really think you’re wrong about this. During their time on the road, the vast majority of Chrysler Corp vehicles with the internal-shunt ammeters (i.e., all of them prior to 1971, and A-bodies through 1975) did not have electrical fires or other problems caused by the ammeter.
On the occasion it happened, there was no difficulty getting it fixed; auto electrical houses—or at least mechanics competent in working with car wiring—were in every city, most towns, and a fair number of hamlets.
The trouble began when the cars got old and, at the same time, it stopped being easy—and then stopped being possible—to get replacement alternators of the original output rating. Many Mopars were originally equipped with 30- to 37-amp alternators, and the heavy-duty option (with larger-gauge wiring and a higher-current ammeter) was a 40-, 50-, or 60-amp unit, as the years went on.
Benchtop repairs and rebuilds gave way to the factory “remanufacturing” industry, which consolidates like crazy, and eventually serviced (or pretended to service) all of the cars in question with just about two alternators: one configured for pre-’70 hookup, and one configured for ’70-up hookup, both with an output of 50, 60, or more amps. Drop one of these in an old car originally equipped with a lower-output alternator, and as soon as there’s a heavy demand placed on the alternator (battery loses a cell, leave your lights on and run down the battery, give someone else a jump start, etc) those wires and connections are going to heat up and eventually make trouble.
But none of that means the engineering was faulty. It was adequate and reasonably reliable for the cars and their equipment as originally specified, equipped, and maintained.
And also no, ammeters are generally not retrofitted (replaced by voltmeters, etc) in exacting restorations—by definition of an exacting restoration.
As for whether an ammeter or a voltmeter is more useful: there are good arguments to be made in favour of both. The fact that voltmeters (real or fake) are more common on today’s vehicles does not imply that Chrysler were wrong to use ammeters in years past.
Thank you (sincerely!) for saying “binnacle”. It’s a word that doesn’t get enough use.
This kind of unquestioned change-for-its-own-sake, these obsessive annual new models (even to the extent of spoiling an excellent design) put American automakers at a big competitive disadvantage; European and Asian makers’ much slower product cycles with running improvements made build quality and quality control much easier and less expensive to achieve.
I’m just going to jump on out there and say this is my favorite dash layout ever. Not an apples to apples comparison, I realize.
Long time T-Bird fan here, but I don’t recognize that one. What year is it? It’s absolutely beautiful! I’ll hazard a guess and say one of the Flair Birds (64-66) or maybe a Bullet Bird (61-63). I didn’t come into the fold until the Aero Bird… my first an 83, which had the leftover instrument panel from the Fox Box era… quite uninspiring compared to THIS.
It’s the dashboard of the 1961-63 generation.
Even though the oil pressure gauge on the 62 Plymouth is not stock, it’s still true that Mopar generally offered more real gauges on more models than either GM or Ford. In fact, especially with GM, the farther up the luxury scale you went, the more likely that no gauges beyond speed and fuel were available, even as an option. For all its faults, the Cimarron was the first Caddy to have anything beyond speedo and fuel since the mid to late 60’s (whenever the temp gauge disappeared), and might be the first Cadillac EVER to offer a tach.
The gaugeless fake-wood-laden dashes of the 70’s were a huge sign that Detroit didn’t understand what was appealing about European luxury cars. GM could call the Seville “international size”, and Ford could pitch the Granada/Monarch as Mercedes clones, but the moment you opened the door and saw the dash, the illusion melted away.
The really sad change from the ’62 to ’65 Mopars was the loss of the transmission pushbuttons. The story I have always heard is that new government fleet purchasing specs, mandating a PRNDL lever, killed the push buttons. True, or another myth?
Government fleet specs in 1965 which led to a law in 1967 was the conclusion the last time we addressed the demise of pushbutton automatics, in the comments on JPC’s article about Lincoln’s pushbuttons here, and originally his comment on the ’59 Dodge CC here. Pushbuttons weren’t outlawed, just the PRNDL order was mandated, but everybody dropped the buttons while they were at it.
Pushbuttons are back. My 2017 Fiat 500e (built by FCA, Chrysler Corp’s descendant) has PRND buttons down where the 500 has its shift lever.
I can wag speculate on part of how the change to lever-and-linkage came about:
After a wonderful garden party the revelers stepped out into a fresh accumulation of slushy Detroit snow.
Snow was no big deal, the seasoned automobile men knew that “rocking” was going to be part of getting underway.
As a carload of Chrysler engineers observed their driver with each shift from forward to reverse repeatedly struggle with steering wheel reach around to awkward controls and the friction of actuating-by-finger cold stiff complex mechanism and cable. Meanwhile, they also looked over and noticed how Ed intuitively and effortlessly rocked his lever-and-linkage actuated Powerglide with nimble gloved fingers handling the gear shift.
No, sir, you’re conflating two things there.
Chrysler dropped the pushbuttons after the 1964 model year—that is two years before the National Traffic and Motor Vehicle Safety Act, two years before the US General Services Administration adopted safety standards for vehicles purchased by the government, and four years before the advent of the first Federal Motor Vehicle Safety Standards. Chrysler’s takeup of shift levers had nothing to do with any Federal safety standards; none existed at the time. It was primarily because they felt with conventional controls they’d sell more Chrysler vehicles to driver’s-ed programs, and this was considered crucial because it was some of a new driver’s first real vehicle exposure, which was thought to be foundational for vehicle preferences.
Moreover, the pushbuttons were regarded as something of a played-out fad; they’d been introduced in 1956. They were dependable and didn’t make trouble (unlike the Rube Goldberg electrical crapmesses on the Edsel and Packard), and were regarded, even by Ralph Nader, as safer than a lever. But the tailfins-and-pushbuttons-for-everything age was in the rearview mirror.
The actual safety standards influence on automatic transmission controls was to force GM to change. Many GM quadrants were arranged P—N-D-L-R. This was (correctly) regarded as a dangerous booby trap, because a forward and reverse position were immediately adjacent with no effective lockout.
In the absence of Federal vehicle safety standards, the General Services Administration drew up their own list of standard equipment required on cars purchased by the government. The list included front and rear seatbelts, nonglare windshield wiper arms, windshield washers, a driver’s sideview mirror, reversing lamps, and automatic transmission controls with no forward and reverse position immediately adjacent. The GSA requirements had the effect of making those items standard equipment even for cars not bought by the government (automakers weren’t about to make government and non-government versions of their cars), which is why things like backup lights and sideview mirrors and screenwashers moved off many models’ option list for ’66 and became basic equipment. GM, having previously issued smug dictates that they were the market leader, so the rest of the industry was just going to have to go along with the GM way, were forced to adopt the safer P—R-N-D-L. When Federal Motor Vehicle Safety Standard № 102 then came in, it stipulated that a neutral position shall be located between forward drive and reverse drive positions, re-sealing the fate of GM’s unsafe design.
I believe that Studebaker was the only manufacturer still using the old GM-style quadrant (PNDLR) after 1964 models. They kept it through the end in 1966. As a Canadian manufacturer for its last 2 years, American GSA purchasing specs were irrelevant.
Well, more to the point, the US Government wasn’t buying many Studebakers…!
After Townsend took over corporate leadership, the corporation conducted a survey of owners of non-Chrysler Corporation cars. It found that, for a sizable percentage of potential customers, the pushbutton arrangement alone was enough to prevent consideration of any Chrysler Corporation vehicle.
Remember that Chrysler Corporation’s market share had dipped to about 10 percent for 1962, so the corporation desperately needed conquest sales if it wanted to increase both its overall sales and its market share. The pushbuttons were completely gone by the 1965 model year.
At any rate, the hot set-up by then was a console-mounted floor shifter for both automatics and manuals.
I suppose if simplicity and legibility are your primary concerns then the Plymouth dash is pretty good. 🙂
However my vote for “best” speedometer is found across the showroom in a Chrysler.
Electroluminescent lighting and Wurlitzer styling, what’s not to like,
The 1997-1998 Lincoln Mark was really nice as well. Curvacious.
When optioned with factory Air Conditioning; were the A/C controls included with the other heater & defroster push buttons; or was the A/C on separate knobs/push buttons?
Included. Buttons, with or without aircon, were “Off”, “Heat”, “Def”, and “Cool”. It was a fully-integral heat-A/C system which used the reheat principle (compressor operated in defog mode to wring moisture out of the air for more effective defogging). Read about it here.
An in-dash #HVAC system, that heated, cooled and dehumidified (SO very important here in Hot and Humid New Orleans!), with a FOUR speed blower motor, when Fords were still using 10 year old “Knee Knocker” technology units.
I believe that “Excellence Thru Engineering” was Mopar’s slogan in this time period? A correct and apt one.
They had Chrysler Airtemp in-house.
Yeah, no kidding. And that axial-flow blower was really keen—it moved heaps of air very quietly. There’s more detail about it in this SAE paper. But they abandoned it, I think for ’65, and went to a conventional radial-flow squirrel cage blower, which I’m guessing was cheaper and might have allowed a smaller box behind the dash.
Mark, Of minor note, it’s not that the blower has FOUR speeds, it’s that the switch is multi-functional.
The blower provides two speeds for heat and two speeds for AC. Two speeds for each mode, with heat’s high and AC’s low being the same speed.
Hmmmmmmmmm…….
According to Daniel Stern’s link the first two fan speed choices are fresh air selections when using the A/C option; then the third and fourth fan speeds are recirculating mode for maximum cooling.
Perhaps I am wrong; but this sounds like four speeds for the A/C option fan blower?
Agreed. It looks like a 4 speed fan switch which also controlled the opening and closing of the fresh air damper. I normally don’t like HVAC controls that combine functions like that but the combination is actually pretty sensible.
I am guessing that the odds of a ’62 Plymouth factory A/C owner, either then or now, posting his/her observations here would be rather slim……
The blower has three speeds. Low and medium for fresh air (operational with heater and A/C), medium and high for recirculated air (A/C only; those two positions are inactive with the heater operating). See page 4.
Which means you can have:
Low fan speed, fresh air: heat or A/C
Medium fan speed, fresh air: heat or A/C
Medium fan speed, recirculated air: A/C
High fan speed, recirculated air: A/C
Three speeds for the blower when running A/C, two speeds when running heat.
All I could get at the link was a one page preview.
Anyway, introduction news aside, I think it’ll be found that with production units “heat” (disengaged compressor) had two speed choices and AC (engaged compressor) had two speed choices, with overlap between the two.
Disregarding what the control indicates and focusing on actual blower speed:
The blower would operate at two reduced (via resister) blower speeds with a third maximum speed (direct power) reserved for “Max” AC.
In other words, the blower would operate at Low rpm in heat mode only; at Medium rpm for either heat or blend AC; at High rpm for “Max” (no blend) AC mode only.
So two speed options for heat; one speed option for “blend” AC; one speed option for all-out (no blend) AC.
Look down at the bottom of the page, and you’ll see the “Go To Page 2” link, which you can click to go to the next page, whereon you’ll find a “Go To Page 3” link, and so on and on.
The blower has three speeds. Low and medium for fresh air (operational with heater and A/C), medium and high for recirculated air (A/C only; those two positions are inactive with the heater operating). See page 4.
Which means you can have:
Low fan speed, fresh air: heat or A/C
Medium fan speed, fresh air: heat or A/C
Medium fan speed, recirculated air: A/C
High fan speed, recirculated air: A/C
Three speeds for the blower when running A/C, two speeds when running heat.
Given 1962 technology; that multi-function fan switch must have been the size of a man’s fist!
Not so giant as all that; see it here (with the separate vacuum switch and bracket attached).
The Mopar variable-speed windshield wiper switches of that time were bulkier than this.
Thanks. Sorry Dan I was at the SAE link where I could get just one page of meat; although I’d be interested in more from the SAE piece.
Yes, the Service Reference clearly explains switch function.
Notice that it’s explained that selecting Defrost disables compressor operation? Odd. Maybe the practical value of dehumidified defrost air wasn’t recognized yet?
That is interesting, isn’t it? They had all the pieces in front of them—page 2 says the air flows through the evaporator where it’s cooled and dehumidified when the air conditioning’s operating. Then as it passes through the heater core, it’s reheated to a comfortable temperature before it goes to the distribution ducts.—but the light bulbs above their heads must’ve burned out before they were quite done with the job. ¯_(ツ)_/¯
It wouldn’t be too awfully difficult to field-fix this omission and have the compressor run in defog mode, not that there’s anyone left who cares.
(The way to read the whole SAE paper is to buy it at the linked site)