90 XJ Cruise Troubleshooting

Ripping the column apart is dead easy - disconnect the battery (most important), undo 2 screws at the back of the column, check you disconnected the battery again (!), remove airbag cover, remove airbag connector, lift out airbag carefully and the T wiring going to each of the 2 switches and the clockspring is apparent. 15 min job to disassemble.

When you said it "worked sporadically" before, what were the symptoms ?

Dave Milne, Scotland '91 Grand Wagoneer, '99 TJ

I may be mistaken about the sporadic nature at first - I only had the car for a week or two before I took it to Jeep for extensive repairs. At first, it just didn't seem to work at all. But a few days later, I realized it was just "sluggish" - ie. it took about 5 seconds for the cable to take up the slack - or at least that's what it seemed like it was doing. After I realized that, I believe it worked most of the time. Unfortunately, I can't remember because I was more concerned with more important problems, that I ended up correcting myself after $3k was spent at Jeep. When I got it back, the cruise didn't function at all.

When I disconnect the vacuum line after the car has sat for several hours there is a hiss, so it is holding vacuum OK. I suspect the fault is either in the control module under the dash (connections tight & clean), or the switch itself.

Another possible red herring - the dealership installed a recall item on the brake switch that locks the shifter unless the brake is depressed. I am wondering if this installation may have been botched, telling my cruise that the brake is on. However, it seems to operate correctly, the brake lights aren't on all the time or anything. I would assume it is either engaged or disengaged. I would assume the identical signal is sent to the cruise control module, but perhaps there are two switches.

No airbags on this baby, so the column should come apart a little quicker. But the manual shows some sort of tool for depressing something to get the wheel off. That is why I balked. Also, there seems to be a small trap door at the bottom of the column where it contacts the dash. Can that just be pried out, or will I break it?

Ok, its obviously slightly different to the TJ/ later XJ one. If it is taking 5 seconds for the cable to take up the slack, perhaps it isn't holding a vaccuum as well as you think. The TJ takes its sensor from the normal brake light switch + clutch interlock switch, so I doubt that whatever got installed is at fault. Do you have to take the wheel off to see if the wires are making it to the steering wheel switches ? I wouldn't have thought so ; you don't for the airbag version which has the switches on the wheel.

Dave Milne, Scotland '91 Grand Wagoneer, '99 TJ

IIRC the 90 XJ has a trun signal mounted cruise control. The steering column is a Saginaw (GM) part. The controls have a separate harness with a connector at the bottom of the column. There is no need to remove the stalk to test it.

OTOH the vacuum lines behind the battery tend to rot from the acid might want to check that out.

Look under the column above the pedals. The plastic yellow box (approx 4"x4") is the cruise "computer". I fixed mine twice in the last 15 years by simply unplugging and replugging the electric connector to this box. Quick and easy. Give it a try and let us know what fixes it. Good luck - Joe 90XJ