Ryderbike1

I was doing a wheel swap the other day to put a ZJ wheel on my 01 XJ and managed to connect the horn to one of the cruse control wires by accident when I was adapting the clock spring. Now I’ve got no cruse control. The dash light comes on for the first minute or so after turning the key and I can hear the solenoid engaging but then it flips itself off and won’t come back on until I cycle the ignition again. I tried swapping the ECM with a donor one and the problem persists. I’m now leaning on possibly a short between the ECM and the vacuums solenoid.

And before anyone comments about it, no it’s not a vacuum leak. I’ve patched several of those over the years. This is definitely an electrical problem.

Has anyone encountered this before? I’ve found a few other threads on here with similar problems but none seem to come to a solution.

lawsoncl

It's possible you fried the cruise control switch, which connects various resistances to signal what button was pushed. The resistance values are different for pre-99 Cherokees and might be different on the ZJ wheel as well, so this could be a compatibility issue. If you have a meter, check that the resistance values look right. Worst case would be melted wiring in the clock spring.

From a recent thread:
99-01 Switches resistance values:
20k resistance when no switches pressed

Clicking the:
on/off = 500 ohm
Set = 7k ohm
Resume/Accel = 15k ohm
Cancel = 1.2k ohm
Coast = 2.9k ohm

Tolerances: Roughly 10%.

Ryderbike1

I’ve been banging my head against this trying to figure it out. I suppose I should have explained a little bit more everything that went into this project.

I realized pretty quickly that the ZJ MUX was different then the XJ one so I got to work harvesting the XJ resistors to hack into the ZJ buttons. That was a lot harder then I expected because the ZJ one had a direct short as the cancel button instead of another resistor so it involved cutting traces and reworking the entire button mechanisms with tiny little wires. But it seemed to all work out fine. The resistors measured to within tolerance of what they should and all the buttons were clicking.

After it didn’t work using the ZJ clock spring trimmed to fit the XJ steering column my first test was to use the original working XJ clock spring. I also swapped in a spare ECM (it caused a bad misfire but I knew cruse worked on it) and that didn’t change the symptoms any either.

I’m now suspecting that all my solder work and excessive heat on these 20+ year old resistors caused a failure in one or more of them that showed a good value with a multimeter but would fail with any actual current running through it. I had to buy a new/old XJ cruse button because I cannibalized my original and I’ll test that once it comes in the mail.

Also the resistor values according to the color codes on them are as follows:
on/off = 464 ohm
Set = 5490k ohm
Resume/Accel = 15400 ohm
Cancel = 1240 ohm
Coast = 2940 ohm

Those seem to match yours except for the set being off by about ~1k ohms. So I’m not sure what that’s all about. How sure are you that those were for the 99-01? Physical measurements and the value codes on the resistor both came back to within 20 mah of that so idk.

wlewis

lawsoncl, would you happen to have the resistance values for 98 Cherokee?

lawsoncl

I don't have a 98 FSM, so instead I'll show off my Google-Fu skills:
From https://www.naxja.org/forum/archive/...t-1038194.html

Resistances for each button, 95-96 (pin 1 is at left with connector latch at bottom looking at back of switch):
No switches depressed: 806 ohms (tolerance 8 ohms) from pin 1 to pin 2
Cruise on switch depressed: 909 ohms (tolerance 9 ohms) from pin 2 to pin 3
Resume/accel switch depressed: 15400 ohms (tolerance 154 ohms) from pin 2 to pin 3
Set/coast switch depressed:
6650 ohms (tolerance 66 ohms) from pin 2 to pin 3

Resistances for each button, 97-98:
No switches depressed: open circuit
Cruise on switch depressed: 909 ohms (tolerance 9 ohms)
Resume/accel switch depressed: 15400 ohms (tolerance 154 ohms)
Set switch depressed:
6650 ohms (tolerance 66 ohms)
Coast switch depressed: 2940 ohms (tolerance 29 ohms)
Cancel switch depressed: 0 ohms (short circuit)