QuestionOur 1999 Gmc Jimmy is stuck in 4 wheel drive low and we can not get it back into 2 wheel drive. It started at first by flasing on the 4 Low button on the dash when in 2 wheel. When you would stop or put it in Nuetral it would lock in 4 Low. Now today when we went to start it up it went into 4 Low and we can not get it to shift back in 2 wheel. Any idea what would cause this. Could it be the switch going out or in the front end.
AnswerVicky,
I'm not familiar with the system used on the GMC, but I would suspect a faulty switch, or vacuum line. On some vehicles, this can be caused by a bad electrical ground, or broken wire leading to the transfer case.
I would suggest that you purchase a repair manual for your GMC. A Chilton's or a Hayne's manual can be purchased at most auto parts stores for $20. They have a lot of information on basic trouble shooting, and repairs, including diagrams of the vacuum lines, and electrical wiring. They, also explain how to test for problems such as yours. These manuals are designed for a year or range of years for specific vehicles, and are invaluable if you are planning on doing any repairs, or maintenance yourself.
If you don't wish to check this out yourself, try to find a reputable shop that is dedicated to working on 4-wheel drives, and see if they will troubleshoot your problem. Most shops will take a look at the problem, and give you a free estimate.
Carl
