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1998 GMC Jimmy

I have a 1998 GMC Jimmy and when I went to sell it and a prospective buyer test drove it, it wouldn’t go out of 4 wheel drive. Murphy’s Law, of course, this couple loved my vehicle, drove 2 hours to buy and would have on the spot, but this $% happened and now I have to get it fixed before they buy it or have anyone else look at it. Does anyone know where we should start? My friend thought it was the vacumn lines froze up and took it apart but nothing will make it work. Is there an actuator that goes bad? The motor is working fine. Someone suggested that battery acid gets on some of the components and causing problems, but that doesn’t seem to be it. Please help, this vehicle is as good as sold as long as I get this issue fixed ASAP. They are sooooooo interested in buying it and willing to wait until we get if fixed and come back to seal the deal. Thanks for any and all advice!!! Jane aka zigamodium

Electronic shift, try:

You may just have a bad control switch (In the dash) or you may have a faulty transfer case control module. (located to the left of the instrument cluster behind the headlight switch) (In GMs).

Before tearing that out, check for loose or broken wires at the transfer case.

My TCCM is on the passenber side under the kick panel. It appears to be fine. what is it that you are referring to on the left of insturment panel behind the headlight switch?

Like I said in my post: transfer case control module. (It works as a command computer for the shift motor in the transfer case)
In my '02 Tahoe 4x4 the module is a silver colored electrical box.
Very awkward to get to.

I have no idea if your '98 Jimmy is set up the same way. To find where (and if) it is in your truck, you may need to look at a wiring schematic.

I wouldn’t put a lot of faith in 10 year old transfer case switches.

I’ve been told by friends who own GM 4x4s that it’s not uncommon for these switches to go haywire.

Have you kept trying to get the switch to work? Sometimes spraying electrical contact cleaner on the connections will clear the problem, (not always though).

You may have tried all the tricks already. Switch back and forth from 4 low to 4hi to 2hi etc and see what happens. Good luck.

I also have a 98 Jimmy 4wd, two years ago I also experienced the- wont come out of the 4wd mode, I took it to my private mechanic who said it was the Transfer Case Control Module,…however my mechanic got it out of 4WD my placing the transmission in neutral I believe then pushing the 2WD on the console (says so in owners manual) however is a dealer only part, which cost me $560… sorry to say… If your light indicator on the console that shows what mode your in, 2W, 4W, 4L is flickering, or will stay on for awhile, then shuts off, (which mine eventually did) I took it to the dealer who advise me after they checked for the error ‘code’ that it was again the module, unfortunatley I didnt know the difference and had it replaced, which made no impact on the light, so I returned also a dealer part, and it was the switch which cost me $80… the price of having a 4WD vehicle…