I was driving my wife's 97 S10 Blazer today with the 4.3L and noticed the 2wd and 4wd pushbutton lights started to flash back and forth randomly. The 4wd light finally stayed on while I was doing 70 on the highway. I did not hear any unusual sounds such as the transfer case or front axle engaging. It finally switched back over to the 2wd light. I stopped the Blazer and it went into and out of 4wd high with no problems. Could this be a problem with the vacuum switch or the dash switch.

The only problem I ever had with the 4wd is when I knocked the vacuum line off the ball on under the hood. When I realized it would not go into 4wd, I reconnected the line and everything was ok...

Any help would be appreciated...

Thanks...

Tom

My 97 was doing that too...couldn't even get the 4wd to engage after awhile. In a round about way we figured out that it was a vacuum line problem...we replaced the Transfer case switch ...(16 bucks, part number 730-1639 NAPA). The switch was faulty. Not only did it not let the 4wd drive engage...but also was allowing tranny fluid into my vacuum lines and filled up my vacuum ball with tranny fluid and who knows what else. Hope this helps.

Caredy

My 97 was doing that too...couldn't even get the 4wd to engage after awhile. In a round about way we figured out that it was a vacuum line problem...we replaced the Transfer case switch ...(16 bucks, part number 730-1639 NAPA). The switch was faulty. Not only did it not let the 4wd drive engage...but also was allowing tranny fluid into my vacuum lines and filled up my vacuum ball with tranny fluid and who knows what else. Hope this helps.

Caredy

Thanks for the response, I really appreciate it. I will order the part today and check all the vacuum lines tonight...

Thanks again...

Tom

I read a number of these posts to know GM is getting away with what
they should repair as a recall. The 4Wheel Transfer Switch* is bad on
1995-2000. I had it checked and repaired several times. I even sued
GM and won through LemonLaws USA 1-800-LemonLaw
Kimmel&Silverman 30 East Butler Pike Ambler PA 19002
General Motors thinks they can get away with ripping you off.
If you have things going wrong with your warranty GM SUV Car or
Van get it serviced or call the lawyer LemonLaw..
www.lemonlaw.com


* For people who purchased a new chevy blazer 1995-2000.