oem cruise control. pressing the "on" button on the steering wheel, dash light does not come on. tried to set speed just for the heck of it, doesn't work. break lights do work. Also I have good vacuum at the servo.
I have found a lot of posts with "light comes on cruise doesn't work" but none with my situation. can someone give me an idea were to continue t-shooting and maybe a wiring schematic so I can visualize the circuit and maybe get an idea of what it takes to get the cruise light to come on initially. I have an electronics degree so don't worry about speaking in lay terms.
Thanks, A.J.
Cruise controls are a fairly simple mechanism, at least the aftermarket ones are. For example the connections you need for an aftermarket cruise are Ground, Accessory power, Constant (hot) side of brake lights, and Ground (cold) side of brakes lights, VSS, then attach to throttle. They have a tach connection, but most units you ground the tach, unless it is a manual transmission then you can hook it up, or ground it and use a clutch switch. And of course the Servo that holds the throttle cable.
Many people think that to disengage the cruise by pressing the brake is because the cruise brain sees positve voltage from the brake lights, however it is actually the absence of Ground that causes the cruise to stop.
I don't know if any thing I've said here will help you but it may give you a place to start. Most cruise controls are similar but sometimes the factory ones are a little different.
By the way, I just noticed that your truck is a diesel. First thing you need to see is if you have a throttle cable. If not then your unit is a drive by wire and that is all electronic. If you do have a cable then you can check any of the stuff I stated above.
update... I was on a long boring road trip and decided to raise the tilt steering and then hit the cruise on/off button, to my amazement the cruise light came on and i was able to set the speed, worked great.. and has worked ever since just by having the tilt steering up. not the best way to drive though..I am suspecting the obvious now, maybe a key pad issue or a wire has a loose connection. can get to the wires that are on the outside of the metal steering column but cannot figure out how to get to the wires that go all the way to the key pad on the steering wheel were the air bag is located. anybody know how to do this?
Pull airbag. The wiring goes through what's called a "clockspring" from the column to the actual wheel. If you pull off your steering column shroud, you will see the connections at the back of the wheel. Airbag connector will be yellow, all else is on the other plug. More than likely, you have a broken wire in the harness where it passes the tilt pivot point on the column.
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Wherever I go, that is where I end up......