Cruise Control trouble shooting 96 4.0 AX-15

96 4.0 ax-15

Performed a junk yard cruise control upgrade. Parts from another 96 jeep.
Servo, buttons cluster, and clockspring


Cruise will turn on. (green light turns on) Any attempt to "set" the cruise, the cruise control turns off. (speed was 65 mph in 5th gear) It wont turn back on until you shut the ignition off and restart it. (not a short?) No CEL.

Vaccum pressure is good. Via HVAC works.
Horn works.
No airbag light warning

The brake lights work when I press on the brake pedal. (actually replace this switch less than 20K ago)

Not sure if there is a clutch switch. Not sure is even necessary.


Any ideas?
Seems like a vaccum leak but, HVAC works. I have gone over the vaccum lines and last look pressure was good.


Thanks.

On a 96 the airbag light warning will never happen since it's a mechanical, self contained unit.

This sounds like the brake switch might not be doing its job fully (there are multiple sets of contacts, one for the lights, one for the TCU, and I think maybe one for the ECU for cruise usage.) Sounds like you have everything set up right, sadly I'm not all that good with cruise control stuff. My bet is brake light switch issue or maybe the button cluster is different manual vs automatic, I'll have to check that but I doubt it.

did you replace the brake light switch with the one from the parts jeep that you got the cruise from?

purchased a new brake switch