4 Wheel Drive/SUVs: 1999 GMC Envoy, chevrolet gmc, gmc dealer

Question
My service 4W Drive light is coming on about 1x a week. It stays on until I turn the car off. It does not come back when I start the car only when I am driving. Does this mean something is wrong or that it needs to be serviced? Is this expensive?

Answer
Sharon,

The best thing to do is take it to a transmission shop or the Chevrolet/GMC dealer and have it scanned for codes. If there is a problem causing the light it will tell the technician exactly what it is. Doing some research, I found that a lot of times in General Motors vehicles, when the "service 4 wheel drive" light comes on most of the time the problem lies in the 4 wheel drive switch on the dash itself. The cost is around $60 for the part depending on your location and it may be your problem

Hope it helps
Matt