We have a '93 S10. In November, the 4WD hi wouldn't engage. We bought it to our mechanic, and he replaced the computer board for the 4WD three times. Each time, we'd try out the 4WD hi, then disengage. After trying it again, the 4WD hi wouldn't engage, although Low does.

It's a push button switch.

We've tried in park, drive, and neutral. The mechanic is out of ideas, and says he tried everything. I don't want to be out $600!!

Suggestions?

Thanks!!

man oh man, i would be firing your mechanic for making you install the part three times! a faulty component is only going to happen once.....it's fluky enough that it was possibly faulty in the first place but not a second time! anyways on to your problem, i think there is a relay in there that the switch activates, one for high, one for low.....possibly the relay is sticking. I will look on my Mitchel program for you, i'm not as familiar with the electronic transfer case, i'll get back to you...keep me posted.

i am having almost the same problem. the switch turns on and I can hear it engage in 4wd lo but, when I shut it off I hear nothing but, the switch does turn off. What can I do?