Over the span of time, I’ve added speed control to a number of vehicles, including the following cars:
The Soul Survivor (1974 Mustang II)
A 1985 Mazda RX-7
The El Kylemino (1987 El Camino)
Our 1991 Mazda Miata
A 1992 Isuzu Rodeo
In every case, I installed the factory system using recycled parts. This requires an understanding of cruise control systems so I could gather the needed parts, and then troubleshoot the system after installation (when needed). Therefore, let’s look at cruise control system designs and review how the technology has evolved over the years.
To add cruise control to any car, you really only need three new parts- A vacuum actuator, a control box, and an ON/OFF switch for driver control. The system needs additional switches and sensors, but in many cases these parts are already present in the car, and the cruise control system just “piggybacks” on their existing functions.
During operation, the control box monitors vehicle speed and commands the actuator to open and close the throttle to match the desired speed.
It also monitors the brake system, usually the brake light circuit, a speed input, and a redundant safety system connected to the brake system to ensure the system shuts down anytime the brakes are applied.
More sophisticated systems add connections to the neutral switch on automatics or the clutch pedal position switch on manual transmissions. This feature keeps the engine from over-revving should the driver disengage the clutch or move the transmission selector to neutral.
Not all manufacturers ponied up for the switches and wiring needed track the transmission status on early systems. I remember my knee knocking the transmission selector lever on my Dad’s ’76 Mercury Monarch into neutral (at speed on I-80), and discovering the engine revved pretty darn high with an open throttle and no load… Nowadays, due to both safety concerns and available computerized data, pretty much all systems monitor these inputs.
Because engine control systems in the seventies did not monitor vehicle speed (or much of anything…), early cruise systems also included a built in speed sensor. The electronics were also less sophisticated, so these systems often used mechanical safety systems rather than additional electrical inputs to the control box.
This picture shows a typical early control unit as used by GM. Mounted under-hood, it connected to the speedometer cable for the speed input. To run the speedometer, a second cable ran from from the control unit to the gauge assembly. The control unit also included electrical connections, a hose to an engine vacuum source, and a vacuum line to the throttle actuator. Another vacuum line connected to a brake pedal dump valve, which bled off vacuum anytime the driver stepped on the brakes.
Over time, Cruise Control systems have evolved to make greater use of electronic inputs and sensors. The control box and actuator may be in the same location, or may be separate. Starting in the mid eighties, vacuum actuators started to disappear, replaced by motor driven actuators. But the systems still used the same three basic components, until drive by wire throttles became the dominant under-hood technology.
With the advent of drive by wire systems, the Powertrain Control Module (PCM) now monitors vehicle speed and brake inputs, and uses an actuator to control throttle position. Because of this, a drive by wire system only needs a Cruise Control switch connected to the PCM. At least in theory. It’s not always that simple, but I’ll cover things in detail when we get there.
Over the next few posts, I’ll review what it took to install cruise control in my cars, starting with the Japanese models. In all my cars, I installed the complete factory system, including all needed safety systems. From there, we’ll talk about the domestic systems I’ve installed, and wrap things up by looking at an aftermarket cruise system that piggybacks onto the drive by wire system in my 2009 Honda Fit.
I doubt many people will follow my lead and install cruise control systems on their personal cars, but you may find the specifics on each system interesting, and could pick up a few tips that will come in handy down the road.
Dave, as someone who loves “improving” old cars, I love your technical articles! Looking forward to the next installments….
Although I have retrofitted only two cruise controls and it was done 40 years ago, I remember them pretty well. One was on a friend’s car, one was on my own. I also bought a used car with an aftermarket cruise control.
I’m looking forward to reading about how yours went.
Of course we are not considering the El Cheapo universal add-ons from JC Whitney, which were nothing but throttle locks. There were no claims for maintaining speed on uphills because they couldn’t. I do think there was a device to release it when brake was applied. At least I would hope so!
Cruise is one of those features I never missed – until I had a car with it. In my case it was a 1963 Cadillac. Those really early systems would be an interesting dive.
I have always suspected that cruise was one of those features pretty well wired in and only lacking one or two key components. I look forward to learning more about this.
I also never missed it until I had it.
But in older cars (OK, maybe not your ’63 Cadillac), the engine was noisy and rough enough that it was easy to maintain a constant speed just by listening to the engine. In newer cars however, it’s easy to let your attention lapse momentarily and then suddenly find yourself driving 80 mph. In my Mazda 323 (my last car without cruise control), that was rather unlikely to happen.
If you think you miss it on a car, try doing 150-200 mile stretches on a motorcycle, death gripping the throttle all the way. Twenty five years ago, I got addicted to the simple mechanical throttle lock to ease the wrist pressure. You can imagine my joy at my first electronic cruise control on my Gold Wing, and the one on the Electra Glide is better giving me the equivalent of a car’s ‘cancel’ button so I can turn it off without flashing the brake lights.
Transducer? What’s Rocky Horror got to do with this?
It’ll seduce ya
I added it to my daughter’s 03 CV, total install time about 15 min, all that was needed was the control unit and steering wheel, and her steering wheel was in sad shape to start off with anyway.
Unfortunately my 09 E-150 is drive by wire and that means wiping the current engine calibration and installing the one with cruise, along with the steering wheel, so yeah considering its normal use it will not be getting cruise. I’m surprised that will all the things that you can turn on or off by changing a digit or two in the code that cruise isn’t one of them.
While I’m not generally a fan of aftermarket Cruise Systems, there’s a pretty good solution for drive by wire cars which does NOT require hacking into the car’s PCM.
I’ll cover it in a couple of weeks when I wrap up this cruise series.
I find the aftermarket units that are available for that vehicle far more invasive than uploading a new calibration and simply undesirable. Not only that it is not any cheaper than paying the Ford dealer to upload the new calibration and using a junk yard steering wheel.
It just annoys me that I can’t change a 0 to a 1 in a single line of code and have it work when I can and have changed many things on it and my other vehicles that simply. OK some require up to 4 digits be changed or changes in two modules, like tire size on my F-250.
“I find the aftermarket units that are available for that vehicle”
Your comment led me to do some checking, and my preferred solution is not offered for any ’09 Ford trucks (surprising, given the number of units on the road). But I agree- Other aftermarket options are undesirable.
And for that van I certainly would have done it if it was doable for $20-$30 and 15 or 20 min like my Daughter’s car, but since I’d only use it once or twice a year on the van it isn’t worth any more than that to me.
I’ve only added cruise control to one vehicle. That was my 1983 Honda XL600R motorcycle, in anticipation of my trip to Alaska and the Canadian Arctic 32 years ago. That was a quick installation job, since it consisted of a plastic over-center clamp that fit over the the throttle twist grip. I used it quite a bit, especially as the XL was easy to ride hands free which let me stretch, take photos etc while riding. However, I’ve never felt the need for cruise on a bike since, and I’m always puzzled when I read a review of a modern “ride by wire” bike where the bemoan the lack of cruise, pointing out that it’s just a few dollars extra for a switch and maybe a few wires, as all the sensors already exist on modern bikes. Both my current bikes are old tech, with carbs and no ABS, so if I added CC it would have to be the old throttle clamp again.
At the time I added it to my XL, I don’t think I had owned a car with cruise, which changed when I bought my Land Cruiser in 1995. Since replacing our ‘93 Corolla with the Forester in ’04, we’ve always had it, but I rarely use unless my right leg cramps up.
It depends on the distance you’re doing at a stretch. Both my Gold Wing and Electra Glide are capable of 200+ miles per tankful, which for me is only limited to the range of my bladder which is usually around 150-175. As that’s roughly 3 to 3-1/2 hours riding time, the wrist can get awful tired.
If my memory serves me well, you’re talking like something around 2 to 2-1/2 gallons on a stock XL tank, so you’re going to be forced to break a lot more often in your riding stretches.
Anyone is more than welcome to have the cruise control off any of my cars, I never use it. I didn’t even check if it worked before I bought them.
To be fair, I only use my Cruise Control about ten days a year. It’s an utterly useless feature in LA traffic.
However, those ten days are all highway driving on open western roads, and cruise control offers me these benefits:
1) I can set a speed 6-8 MPH over the posted limit, and never worry about a speeding ticket or lose track of my speed. As ERIK703 stated above, ” In newer cars it’s easy to… suddenly find yourself driving 80 mph.”
2) Using cruise, I can extend my driving time by a couple of hours. Because I’m no longer devoting 10-20% of my attention to monitoring speed, I’ve got energy reserves to use at the end of the day.
3) In theory, cruise gives me better fuel economy. I’m not sure I actually see a difference, but there you have it.
I drove 450 miles on Tuesday and it never crossed my mind to use it.
On the old GM vehicles, you could unscrew that speedo cable at the transducer and it’d stop the odometer (so I have heard). I also remember those transducers would go bad and your cruise would “surge”.
Yes used to unscrew it on gm taxi cabs so would it show the miles
I’ve only added cruise once, to my 1G Scion xB. I used the Genuine Scion Accessory kit, which I found NIB on Craigslist for half retail price.
That car still had a cable throttle, so the kit included a transducer. It also included a clutch safety switch, but the car already had the bracket to mount it. Everything else was just wiring. I recall the install taking about 2 hours.
Your experience is very typical for Asian Vehicles – as we’ll see when I review the Miata, Rodeo, an RX-7 installations next week.
I know somebody who added cruise to a Yaris simply by taking the junkyard sourced switch panel, popping the block-off plug, and plugging it in. The underhood stuff was already there.
Strangely, the first US Toyota Prius (2000-2003) came without cruise, apparently to squeak the price under US$20K. Obviously a full hybrid is “drive-by-wire”, and it knows road speed, etc. Wiring, software and indicator light were already there. Just had to add the control stalk and a brake pedal switch. It was a common owner mod.
Neither did the 2nd Gen Prius… Technically. There was an “ultra-base” model that wasn’t sold to the general public, only to fleets. And to cut the price to the bone, it did not have CC.
I added CC to a 2000 Frontier that inexplicably didn’t have it from the factory. My buddy had a NOS Audiovox cruise control sitting in his garage, something he bought back in 1980 but never used. It required four magnets to be installed on the driveshaft with double-sticky tape and wire and had a Zilog Z80 eight-bit processor. Aside from not having a clutch switch, it worked perfectly. Pushing the clutch in or bumping the trans into neutral gave a loud demonstration of the KA24DE’s RPM governor.
I’m glad to hear you had good luck with the kit, but using double backed tape to mount sensor parts is exactly why I’m not a fan of aftermarket systems.
Very clean installation by the way- Taking the time to do it right helps explain why the system continues to work.
Five years ago when I was pricing them aftermarket CCs use the vehicle speed sensor, so no magnets.
That’s probably the same kit that I installed on my ’88 Kingcab way back in the ’90s. My kit may have been newer since it had zip ties instead of wires to hold the magnets to the drive shaft. I bought it on clearance, open box with the instructions missing. There were only a couple of pages from the french instructions with the list of parts in the kit and settings for various vehicles way older than my Nissan. It took a bit of trial and error road test to set up but it was simple enough. The kit had a pick-up that goes on the #1 spark plug lead to sense rapid changes in rpm so pushing the the clutch pedal or knocking it out of gear disengaged the cruise control.
I wouldnt mind cruise in my C5 Citroen but I’m not sure it was optional on manual diesels it was a standard fitment on automatics though, I use the personal limiter and cruise control fitted on DAF trucks when I drive them, handy features to keep the big brother speed monitoring feature the company fits happy unfortunately because they are manual roadranger equipped trucks there is no automatic overspeed engine brake fitted that only comes in auto transmission models.
I once had a 2007 Toyota Corolla CE that came without cruise. It had a drive-by-wire system. I ordered a cruise control switch for a Pontiac Vibe from Rock Auto since it was about $30 less than the Toyota switch. Spent an hour installing it. The most difficult part was precision cutting the hole in the side of steering wheel. It worked perfectly, including the “cruise” light in the gauges.
Toyota, Hyundai/Kia and a few others are nice enough that the software for cruise control is already there. Once the hardware is installed it detects it and enables it. When I did an ’08 Corolla I forgot to move the little ground wire from the dummy plug and the horn didn’t work. DOH!
A decade ago, when I was daily driving a ’74 Dart, cruise was at the top of the list of things I missed.
The factory never installed it on an A body, but it is pretty simple to retrofit a system out of a full size Mopar. I had accumulated most of the parts, but never got around to installing it before getting rid of the car.
Actually it was offered starting in in ’75.
Looking forward to future articles, since I would love to add factory cruise to my ’83 5.0L/C4 Ranger 4×4. Hope you cover installs not using the factory wheel switches, as I have a high dollar aftermarket leather wheel, and i’m not switching back to a crappy factory wheel.
In the late 70s and early 80s, I sometimes earned spending money installing aftermarket cruise systems. At the time, the Dana system worked about as well as the factory GM and Ford systems, but took hours to install. Getting the speed sensor and throttle linkage right was more art than science.
I had an ’81 Toyota diesel pickup that I installed an aftermarket cruise on, as well. Dana did not have an electric throttle actuator at the time, so I went with a brand being sold by JC Whitney and one of the department stores (Sears? Penney’s?). It was less satisfactory. In particular, there always seemed to be a bit of contention between the cruise control and the diesel’s mechanical governor. Both were trying to get the engine to run at a steady speed in their own ways.
I noticed that a lot of the van conversion and motor home manufacturers at the time were installing Dana systems instead of the factory cruise, though I imagine they did it for cost reasons.
By the mid or late 80s, most factory systems had caught up with Dana’s feature set and maintained a steadier speed than the aftermarket systems. I would have a hard time recommending one today, as you can retrofit the missing factory parts for less money and time.
The last vehicle that I purchased without factory cruise control was a 1984 Ford Mustang. At this point I no longer remember if it was a factory option and just not installed, or was something not yet offered. My brother, his brother in law and I installed an aftermarket cruise on the Mustang; I have no idea what the brand was but it came from Sears if that helps anyone. The basic installation was straightforward and went quickly; what took longer was adjusting the system to work correctly. We finally managed to adjust the cruise so that it would hold the desired speed without issues. The Mustang was a GT with the 5.0 V8 and a five speed manual transmission, on long inclines you could hear and feel the throttle being eased open to maintain speed. The irony is that I installed the cruise for the purpose of a two week vacation to Toronto and several locations in New York, and, as it turned out that was the only time we used that car for a long trip.
FWIW factory cruise was offered on Fox Mustang right from the start in ’79.
It was even available on 1967-69 Mustangs, then dropped for years until 1979.
Yes, I had it on my 1980 Mustang, which had the controls mounted on a steering wheel that looked suspiciously like the one used by the same year’s LTD.
For Christmas 1971, my dad bought a new 1972 AMC Ambassador. He bought the cruise control kit for it from AMC and installed it himself. I think it took him about a day to do so and get it working correctly.
He disliked the Ambassador so much that he traded it toward a ’73 Mercury Monterey ordered just the way he wanted it. Cruise was included!
This should be interesting my car is drive by wire in fact everything in it is conputer controlled theres a delay when you dip the lights or press the horn while the control module some decides whether you really mean it or not, I though it was faulty but a friend bought a later model Citroen diesel manual that behaves the same way its not a huge delay or anything dangerous just enough that you can tell the switch is activating something else along the way, and C5s are appearing regularly on trademe being wtrecked for parts so the relevant hardware should be available
I’ve had cruise control retro-fitted to three of my cars – an after-market vacuum-actuator system in my 1994 and 1997 Nissan Laurels, and using factory parts in our 2006 Peugeot 307.
For the Laurels it was because I had a 280km daily roundtrip to work and back, and half of that was on motorways, so cruise control made the trip tolerable.
For the Peugeot I wasn’t commuting any more, but just wanted cruise control. I did a bit of research online and found I could just buy the column stalk and plug it in. The Peugeot dealer then plugged into the OBD and turned the cruise on in the vehicle software settings.
The aftermarket kit in the Laurels cost NZ$150ish to buy and about $500ish to install. The Peugeot stalk cost $25 to buy, plus a similar amount for the different steering column shroud with a hole for the stalk, and the dealer charged $150ish to turn it on via OBD.
Fun fact (and watch-out!) with the Peugeot (similar age Citroens would be the same): because our 307 left the factory without cruise control, when the dealer updates the vehicle software at services, the cruise control has to be manually reactivated in the software. They think it’s because the software looks up the VIN number and downloads updates applicable to that VIN’s factory build spec – and the software thinks that our VIN shouldn’t have cruise so defaults it to off in the settings.