The 4WD needs Service light is very similiar to the Service
Engine Soon light. It's telling you that there is either a code
present or in history. You need a scan tool to reset it, and
there is no point in resetting it unless you fix the problem.
Probably needs a new 4WD switch in the dash.
Most likely you need to replace or fix the switch on the dash for the 4WD,
this is a very common problem. Do a search through Google and you will see.
The switches are prone to fail and can be fixed by yourself. Mine failed and
two of my friends failed also with no codes present, if not fixed you could
cause some serious damage as I believe you could have a condition where the
transfer case has not shifted properly. Look for the self repair and try it,
I bet it will fix your problem and it takes like ten to fifteen minutes to
do with your trusty soldering iron. BTW, in two cases the dealer has
misdiagnosed the problem!
This just happened to me. The message reappeared intermittently and I
could find nothing obvious. Then I got stuck in some mud and switched
into 4WD. After I got out, I couldn't swith back into 2WD. I could
switch into auto 4WD though. I figured there was a connection between
that message and something with the switch. The dealer confirmed that
it was a common problem.
On Mon, 28 Jul 2003 23:33:10 GMT, "shiden_kai"
I had this problem with my 2000 z71.. I was told to replace the push button
panel. I went to the dealer and bought a $85 switch. I pulled off the trim
that goes all the way aound the dash.. Took off old switch installed the new
one.. Now it works FINE.. I know sounds to easy but this was my problems.
I don't know if GMC is the same switch or not..
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