On special request (jeebowhite) a guide how to install an aftermarket cruisecontrol in a car with a drive by wire gas pedal.
The guide descibes a Waeco/John Gold cruisecontrol with an electric servo. But it can also be used as a guide for cruise control with a vacuum servo or different brand, VDO or any other.
I don't deserve all the credits for the idea, i thought of doing it this way but later i also saw it in an old VDO install manual. See the pic. (Dutch tekst with it but if you want to know, Google translate is an option ;) )
1) Disconnect the battery.
2) The next part requires some creativity and handy work but you don't have to be a rocket scientist. You will have to make a bracket (actually two) to adapt to your gas pedal.
I first made a mockup from cardboard so i could get things as right as possible. Then with some sheet metal i had laying around, in my case stainless but any sheetmetal at least 2 mm thick will do. If it is thinner it will bend before actuating your pedal.
When i had the cardboard pieces cut i made the right angles in it and taped it so they would stay angled. Then i attached them to my pedal with tape to see if i got it right. Especially important to check is the distance between the 2 brackets. Is there enough clearance between them to move and is the pedal able to travel the complete stroke.
If thats the case, take the cardboard off, make the exact same pieces out of sheetmetal and proceed to the next step.
3) To attach the brackets i had to drill 2 holes in my gaspedal so i removed the pedal. Is easy, in my case 2 nuts to undo and an electrical plug to unplug.
4) When fitting the metal brackets you probably will have to adjust the brackets still a little, i did and after fiddling a bit they were to my liking. I didn't attach the bracket to the moving part of the pedal the same as the VDO pic, i choose to fit it on the side of the pedal instead of the bottom or the top. This way i could make it a bit stronger because i could use the pivot point of the pedal also. Drilled a hole in the sheetmetal at the pivot point, bolted a M6 bolt to it and let the threaded end stick into the hole of the pivotpoint. It isn't connected to the pivotpoint but it just uses it to add a little stability to the sheetmetal bracket.
The other bracket is fairly straight forward, it uses the 2 top connection points of the gas pedal and has just to angles in it.
I did drill 3 holes in it because i couldn't precisely pinpoint the right location for the cable to go through.
5) Put the gas pedal with the brackets attached back in.
6) Now you have to think of a place to put the servo. I had an electric one so i decide the best place was underneath the drivers seat. The cable is run through the middle console so you don't see how it's constructed unless you know where to look.
If you have a vacuum servo it's an other story. If i had installed a vacuum servo i probably would install it under the hood and let the cable run through the firewall to the gas pedal. Reason is that is think the vacuumservo makes more noise. The electric one you can't here working, the vacuum one will have to let out air and let it in. Not sure of the noise part but if you install it under the hood the vacuum line will be shorter so also less changes of air leaks.
7) Now you can connect the steel cable to the bracket of the gaspedal. Make sure the pedal can move freely after you installed the cable! Ain't funny when you're doing 60 miles an hour and the throttle is stuck!
8) Now for the electric part. You need to connect the 12 volt, earth, brake signal (clutch signal but i didn't do that, been driving around 4 years without it in my Mercedes and i don't miss it) and speed signal. You could use the rev. signal but speed signal is preffered. With an automatic you simply can't use the rev signal because an automatic will Always have a little slip so the revs are not stable enough to use for a cruisecontrol.
9) First earth. You can get that from any point on the body or chassis. I got it from a black wire because i had an electric scheme of my car. Just Google for it and there's enough to find.
10) Then 12 volts. Because i had an electric scheme i knew which wire i needed. You need a swithed 12 volt signal, not a constant! Decided i would take it from the ignition switch as i had that uncovered to install the control stalk.
So looked for the right wire, soldered a new wire to it and connected that to the cable harness of the cruisecontrol. Make sure there's a fuse in it, otherwise when something goes wrong you could burn down your car!
11) Speed signal. My radio adapts the volume to the speed i drive so that's where i got my speed signal from. Off course you'll need an electrical scheme to know which wire you need ;)
You can also get it from you're odometer but you will also need an electrical scheme.
12) Signal from you're brake is simple, just connect the appropriate wires from the cruisecontrol to the 2 wires from the brake switch.
13) Clutch signal. You will need an extra switch or if there is a switch already you can use that. As said i didn't connect that and i don't miss it. (And you'll only make the mistake to disengage the clutch while on cruisecontrol once ;) )
14) The brain of the cruisecontrol. If you have a cruisecontrol with combined servo/brain it's easy, you will already have placed the brain in step 6.
If you have a seperate brain the most used option is somewhere underneath the dashboard. I placed it behind my glovebox, all my wires were long enough. You can also place it underneath the steeringcolumn, i attached it with Ty-raps, nothing fancy.
15) The control stalk or pad. If you have an original stalk or pad it's real easy. A pad you can just place anywhere you want and is convenient for you. A stalk is almost always placed on the side of the steering column but you can also place it on the dashboard somewhere next to the steeringwheel. It's what you want and what you will find convenient to operate.
Well, that's about it, included are some pics from my own installation. The advantage of the Waeco/John Gold are you don't have to adjust anything, just follow the instructions from the cruisecontrol to activate it and you're good to go.
Some other brands, VDO for example, will have dipswitches to adjust for the speedsignal and other adjustments.
Just follow the instructions from the cruisecontrol and if you don't have them, like me, Google is your best friend.
I didn't have the original Waeco/John Gold stalk/pad, didn't want to buy it because it isn't that cheap. But i did have 2 VDO stalks so i resoldered that to match the Waeco. Also did that with my Mercedes, Waeco cruiscontrol but original Mercedes stalk at the wheel.
Also thought about using my radio control stalk to control the cruisecontrol. But it's a pita to take apart, i haven't seen this kind of bad plastic on any car before, everything you try to take apart, even so gently, will break. Think they got a good deal on some B spec or China plastic ;) . So after destroying one radio control stalk i abandoned that idea.
I also have a 3 button memory pad with it so i put that on the left side next just above the boot release button. The control stalk is located on the right side of the steeringcolumn, would rather have it on the left side but there no room on that side and i didn't want to loose my remote radio control stalk.