Hey Everyone,

Trying to diagnose a bad cruise control and looking for some further assistance.
I have a 98 Sport V6 Auto

I have replaced the following:

The clockspring, The switches on the steering wheel, the cruise control servo under the hood, i've also replaced the brake switch.
I've taken apart the steering column bezel and so far have not found any wire breaks in the cords.

I backprobed the clock spring wires and with the RED on the LG/B and the black on BK/BL wire i'm getting 4.75 is volts. When i press the buttons the voltage on the back probe changes to a lower number then comes back to 4.75v all the switches cause some change. The light on the dash does not illuminate except for when starting the truck.

Any other things to try would be greatly appreciated. Most of the threads i searched are fairly old and i was hoping someone else had something to try, thanks everyone

 

Check engine lite on? Any pending codes??? I think the PCM disables cruise if something else ain't quite right.... aside from that, sounds like everything else is working the way it is supposed to.

 

The button pads are resistors; The module looks for the various voltage targets for the various functions.

The buttons themselves are prone to wearing out. But you should at least have the CRUISE light come on (not sure where it is on the early dash?) when you mash the Cruise on/off button.

Did cruise work previously?

 

No, it was not working previously. It was a purchase in April, but I’m trying to get everything up and running so I can drive it a bit more often.

i don’t have any codes or lights on the dash. The light doesn’t come on when the buttons are pushed, though they do light up when starting the truck.

I got the new switches and cruise servo from eBay where the sellers said both were tested and working.

i guess I’ll double check that the servo is getting power. Maybe the new brake lamp switch is bad?

 

To my knowledge, which is 01+, the CRUISE light in the dash will turn on whenever the on/off button is pressed. The brake switch will cancel cruise control, but cruise will still be turned on and the lamp illuminated.

Part of me wonders if it's a factory cruise truck. Perhaps the cruise system was added later but never enabled in the PCM.