Hi All! Been racking my brain and searching the web for weeks, found a few people with same issue but no one answered them to solve
So here goes! 99 Blazer, The 4 buttons on the 4x4 switch stays lit all the time. It feels like the trans is surging at lower speeds20-30 mph. If I pull the 4x4 fuse (#15) it drives normal but kills my gas gauge and temp gauge.
Pulled switch, looks fine, but ordered a new one just in case. Pulled the tccm today, doesn't look corroded at all. Would be grateful for any insight on this.

Thanks Guys!

 

Do you hear any excessive clicking sounds coming from the TCCM? When mine went out it acted like it couldn't decide what state to be in with it clicking a lot. What I don't think I had was all of the lights being on on the 4wd switch (I have the 4-button too) but I could be wrong, it was a while ago.

With the fuse in, you say it drives poorly. Can you be more specific about the symptoms? Could it be that the 4wd is actually engaged? Either the 4Hi or Auto-4Hi? The Auto-4hi does automatic engagement and disengagement. Perhaps something is not working properly with it; e.g. it thinks it has been told to be on and also is not functioning properly?

 

 

The clue seems to be the fuse and what in particular it disables. If there is an obvious part to which it supplies power, say the TCCM?, then that could be the part that is not working correctly. I don't know if it is the TCCM or not but that is how I'd go about trying puzzle it out. A wiring schematic would be needed.

Maybe someone else who has had this problem could help out? Anyone?

 

It very well might just be a faulty 4x4 push button switch on the dash??? I am not a mechanic by any stretch, so just a possible though on my end... I have a 98 with the 3 button 4x4 switch so I don't know anything really about the 4 button setup... Good luck and we hope too hear back from you when you get the problem fixed.