lenchito

'98 4.0 Cherokee Classic. The cruise control does not work. Is there a fuse and/or relay for it? I checked the manual for the fuse box and didn't see any reference to it and the black box under to hood did not show anything for Cruise Contol either?

Thanks!

solderjunkie

Cruise is handled through the PCM... the only fuse that would affect it is the brakelamp fuse (fuse 22 in the PDC).

The wheel-mounted cruise switches use a MUX variable-resistance circuit through the clockspring.

Does the cruise light switch on when you activate it?

finneys98xj

Does your ac switch from floor to deforst. If it doesn't it is a vacumm line gone bad.

lenchito

No, the cruise light does not come on. My brake lights all work too? Can the MUX variable-resitance circuit be changed? Through the clockspring?

lenchito

I'll double check, but I'm pretty sure it works fine.

mike37

I had a vacuum line brake right by the cruise control diaphragm
used a short piece of vac line to splice it together works great now

EvilBlackXJ

I think 90% of the time if your cruise isn't working, it has something to do with vacuum. Check for deteriorated hoses, or bad connections.

lenchito

Solderjunkie - can you please expand on the MUX variable-resistance circuit through the clockspring? Is this replaceable? What do you mean through the clockspring?

The light does not come on in the dash and the AC/defroster all work fine, so I an thinking (scary) that it is electrical related.

solderjunkie

The PCM reads a variable-resistance MUX from the steering wheel-mounted controls. This meant fewer wires through the clockspring.

It is best read on a DRB III, which is the factory scantool. With the DRB III, the user can monitor the logic-circuit in the PCM which reads the MUX.

Without a DRB, the at-home owner could only read the signal by backprobing for voltage at the clockspring. The clockspring also carries the current for the airbag and horn, so most people are scared by it.

If you are not scared and you own a digital volt/ohm meter we will continue...

mike37

I don't know if the 98 is different than my 91 but
the vac line was broken and it did not effect any other vac systems
and the cruse control light did not come on until the vac line was fixed then it worked like a charm

Texcuda

Solderjunkie, i'm not scared.

I just got my 99 XJ and the cruise/horn don't work plus the airbag light is on. I was told by previous owner that something was bad in the column and had to be replaced. Is it this clockspring you refer too? Currently the horn is hotwired old school to a button but I want it fixed asap. Any info you can give me on testing and replacing WITHOUT setting off the airbag would be greatly appreciated. Thanx

Chris

Jamie57

Since we're on the subject.
My 98 sport doesn't have cruise but I'd like to add it from the jy or my doner 91 limited. How much of it interchanges or do I need to find a 98 heap?
Thank you oh wise and wonderious sages of the cherokee!

troy fritz

I had a vaccume line by battery break and did the same thing. Splice a rubber hose over it with electrical tape and it will work fine . It fixed mine!

Kyle42

Where did you find the vacuum line? Do you have a link or anything?

MickDime

check the vac canister my leak was on the elbow joint that inserted into it