1999 GMC Jimmy switching to 4WD by itself

Pampersman · October 19, 2005

I have a 1999 GMC Jimmy 4 Door that automatically shifts into 4wd hi and/or low while driving. It just switches automatically without pushing the selector switch buttons. I have replaced the module on the passenger side floor area, no help. I replaced the controller on the transfer case and it was fine for about a month and then it started to switch on it's own again. It will go into 4wd if you select it. At one point I was unable to get it out of 4wd. These parts were replaced twice. Once with a remanufactured and then with brand new. Needless to say it has cost me a lot of time and money!!!! Please, can you help? My brother has checked it out on the ALL DATA where he works and nothing comes up. Please reply with an e-mail to me at [email protected] My name is Pasquale Thank you in advance GM Tech.

GM-Tech · October 19, 2005

Does it actually change, or is it that the lights just light up, but no actual change in the transfer case? Are there any DTC's?

vnuss69 · October 19, 2005

GM TECH, I need assistance, can I email you directly. I am at work and not supposed to use forums.

Thanks

Pampersman · October 20, 2005

Does it actually change, or is it that the lights just light up, but no actual change in the transfer case? Are there any DTC's?

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Pampersman · October 20, 2005

Does it actually change, or is it that the lights just light up, but no actual change in the transfer case? Are there any DTC's?

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GM Tech,

Yes, the transfer case does switch the vehicle into 4wd, sometimes 4Hi and sometimes 4Low. As for DTC's, my brother said that he couldn't get into the 4wd with the scanner they have at their shop. Any other info you need, just let me know. Thanks