I have a 1991 F350 Lariat, which had cruise control on the wheel when I bought it, although the buttons were busted and the wheel was in awful shape. I replaced the wheel with an aftermarket Grant (no cruise control) but after a few years of driving without, I miss the convenience of cruise control, so and I am hoping to rig the "On" and "Set" wires to a single, "big red button" on the dash, which would simply turn the system on and set speed (I don't really need the up and down).

I am guessing that the system uses simple TTL digital signals, and if I can find the lines for each button I could simply pull the correct two low (or high) and the system would set. I was going to clip the wires under the dash where they exit the column and crimp them onto the leads of my switch... anybody have an opinion on this setup?

I pulled the wheel off and saw a 6-pad connector on the mating face of the steering column. I have looked through a few manuals and neither contains any wiring information about what goes to what ... some of them are hot 12V and some appear to be ground. Obviously, it's a little hard to guess-and-check the system since it won't set below 30 MPH, and you can't drive without a steering wheel (or at least, I can't).

Does anybody have a wiring diagram that would explain what is what?

Thanks -- feedback much appreciated!

Cheers,
Alex

 

The Cruise Control system on Ford vehicles is not simple TTL logic levels, it operates in various modes depending on the voltage drop associated with which button is pushed.

Steve83 has some great info here, but I do not see the diagram for the steering wheel w/buttons: 1983 Ford Bronco 90-25-12 Vacuum Cruise pictures, videos, and sounds | SuperMotors.net

A diagram from a 1988 Bronco should match what you have:

 

Thanks! This is super helpful. Looks like I can do what I want to do with 3 splices, a resistor and 2 buttons - "on" by switching dark blue & light blue, and set by switching light blue to ground through either a 120 or 680 ohm resistor.

That should work, right?

Again -- thanks!

Alex