Hey guys I have a 2000 blazer. The 4x4 is not working. It will let me put it in auto 4x4 if I try to put it in 2hi it switches to 4x4 hi. I also can't get it to go into 4low. It says it's in 4hi but only the back wheels spin Any ideas ?

 

ok I just spent 6 weeks with the same beast. so let me save you some time and money.
your not in 4x4 at all by your post. do a self test on the tccm this test has 4 codes it will send you in the right direction. that print out is somewhere on this forum but you will have to search it and I don't mean the search box do it by hand. you tube this issue for better help and visuals, also google this and you will find all of the codes and how to ground the pin 13 on the data plug all of the codes are in the buttons on the dash and will flash to let you know where the problem might be headed to. do not start replacing stuff until you have the problem located.

 

Thanks for the reply. No the truck is not in 4x4 at all still in 2wd despite what the switch says I tried to pull codes but there was. None I checked to make sure I had vac and I do Checked to make sure the cable is working properly and it is Checked that the actuator is working and it is. I did notice that the button lights go dime /out When I press the button I here a click come from under the pass side and the light will switch to what ever I pressed but then go back to where it was befor

 

yep all those need to be checked if you grounded the data plug pin #13 you should get 1 0r more flashing codes on the buttons if not the tccm is shot.

 

So I found the problem in the pass side kick panel there's a box there the wires were
baddy caroded One pin had rotted right off

 

Yep that would be a problem ....Reading the 4 codes as per the other posts only works on the 3 button system , the 4 button system needs a capable reader to access the codes. I have seen where the wire bundle was so corroded that a new terminal end had to be spiced in.