4wd problem 1992 s-10 Blazer

[Matthew196]

When i want to engage 4 wheel drive high, it don't work. But if I engage 4 wheel Low and then go from low to high. Its makes a VERY LOUD grinding noise when I shift from either Reverse or Forward, WITHOUT even hitting the gas pedal???

Its so loud it makes you think your going to blow the transmission!!!

But if you put it back in Neutral and push the 4wd high enough times it will eventually kick out of doing this!!

Plus also the 4wd low works strange sometimes too SOMETIME even when you push the button for 4 wheel LOW it makes BOTH 4 wheel high and low lights come on!!!

The actual dash mounted switch works fine because we took it out and used a ohm-meter to test it and it works great!!!

We have also tried replacing the 4 wheel drive control module located on the main computer for the vehicle!!!

I HOPE to suspect this may be a transfer motor problem, and I am HOPING it has nothing to do with the wiring!!!

If I short the diagnostic terminals, the 4wd switch indicates its a number 2 (encoder circuit fault)....

ANY ideas on how to fix this is GREATLY APPRECIATED!!!! THANKS!!!

[DetroitMuscle]

My 92 is not push button...I thought that was a 94+ design.

[Matthew196]

Yes my 1992 has the push button style of 4 wheel drive!!! However that not the main problem... There only 2 modes however. 4 wheel high and 4 wheel low!!!

The swtich was replaced once before by the dealer because they saw that it was locked into 4 wheel drive (but it was not indicating it was), when they were doing a recall on it, so he replaced the switch as part of the recall and told us we owed them nothing!!!

Any ideas to try rather than replaceing that motor, as that 4 wheel drive engagement motor isn't anything to cheap!!!!

But it is a 1992, and is over a decade old and doing well for everything it takes (snow, sand, rust, salt, and everything else, LOL) for up here in the North Country NY where I live!!!

However I do miss my 4 wheel drive especially in places i go on scouting events where 4 wheel drive is almost REQUIRED for traction in the snow!!!

So any ideas on how to fix the main problem in my first tread is greatly appreciated!!! THNAKS!!!