Hi,

I'm joining to your family with 1997 5.2 V8 ZJ
Its my first jeep and i dont know car well.
I have problem with Cruise Control
I check wire and vacuum hoses and all seems fine.
When i hit On/off button cruise light comes on dash but when i push set nothing happens.
I suspect fuse, do you know where is fuse location

Thank you

 

It could be the cruise control buttons, the brake light switch, or possibly the vehicle speed sensor located on the transfer case.

The brake light switch may be misaligned. This can cause the cruise control to stop working (brake lights work normally). The brake light switch sits on top of the brake pedal. It is supposed to have a clip in it which may eventually fall out.. it can lead to this symptom of having no cruise control, as the brake light switch works itself free over time.

The Vehicle Speed Sensor (VSS) might have had the seal on it go bad. If fluid has gotten into it this can cause the cruise control to stop working. The VSS is located on the transfer case tail housing.

It could be the steering wheel cruise control switches. Those buttons can get worn out and stop working. I copied and pasted another guys fix for the cruise control buttons below..

(copied and pasted)
If you want to fix it, take about 5 minutes and some black vinyl electrical tape and a small screw driver and sit in drivers seat. Use screwdriver to pry the middle of the button to one side to release the pivot point. pop the button out, and then pull the silicon pad out. be careful not to lose the little metal pieces. you will see where the pad is indented from the contacts. put one small strip of tape over the indentations and reassemble. i did mine a couple years ago with no problems. use it everyday on my commute.

 

You’re not really going to find a fuse for the cruise control on your Jeep. Why? The cruise control unit is controlled by the vehicle computer and receives its power supply from the same computer. If power is not being supplied to the speed control servo you want to inspect the stop light switch. The stop light switch, on your vehicle is really 3 switches in one. One part of the switch is for the stoplights. The other two parts are for the cruise control and, if not operating correctly, the cruise control will not operate.

It sounds like the brake light switch or the button/set-switch on the steering wheel might be why the cruise control does not work?

 

My brake lights working properly, this means switch is not culprit?
And i made self diag. 5 times on off key and no error related cruise or vacuum. 12-21-55 errors.

I really want to make it working and any ideas will welcome

 

No, the speed control circuit of the brake light switch can be faulty and you may still have normally functioning brake lights.

You could make sure the brake light switch is properly adjusted at the top of the brake pedal. There is a procedure to follow in the factory service manual.

For a 1996 ZJ (should be the same for 1997 ZJ) the brake light switch has 6 terminals. Terminals #3 and #4 are for the speed control circuit. With the brake light switch plunger pushed inward to the fully retracted position there should normally be continuity between these two terminals.

I think it sounds more likely the cruise control switch/set button on the steering wheel may need repairing or replaced.

The other two possibilities I know of are the Vehicle Speed Sensor and the clockspring. If either of these two things are faulty they can cause loss of cruise control. I would investigate at the brake light switch and the steering wheel cruise switch/set button first though if it were me.

 

Am also trying to find the fault for why the cruise control is not working.
I have a question around the brake light switch possibly being a cause.
if the brake lights are not stuck on, does this mean the brake light switch is working ok ?