I just got my 01 ZR2 Blazer, When driving, after about 4 miles the service 4wd light comes on, this happens on every drive. I have the 4 button 4x4 switch..Sometimes while I am driving it will go from 2 hi to auto 4x4 without pressing anything, and when you press the 2wd button to switch it back, it doesnt switch. On one occasion i saw the 4 low light flashing while on the free way, but it went back to 2wd. Ive tested both 4 hi and 4 low before, and they work.. but sometimes it will stay in 4 wheel drive and wont go back into 2wd when you press the button. You have to turn the truck off for a sec or two and then try to select it again and sometimes it works. I really want to get it fixed because it is the only thing wrong with my truck.

I hear a lot of people getting codes that say its a switch but then they change it and it doesnt fix anything. I don't hear any weird noises, no clicking or anything.

I have not run a scanner yet, but I will next week. If anyone has heard of or has similar problems and could give me some possible causes that would be supreme.

Thank you

 

It could be a faulty switch or even corrosion at the plug on the TCCM.

You can remove, inspect, and clean the plug on the TCCM (located behind the passenger side kick panel) rather easily.

The switch can be tested with a multimeter (search for "NV236+resistance" with an author of "swartlkk" and you should be able to find the pertinent information).

 

Thanks swartlkk, ill try that