i am new here i have a 99 blazer that is stuck in 4 low i have serched this site and many others but still left with questions what motor or vacume lines work what, how do you know if your tccm i working where are the vacume lines on the fire wall,, any help would be apreaciated thankyou

 

If you are stuck in 4lo then you will have to check the voltage at the TCCM and check the Encoder motor on the transfer case. The Encoder motor is located next to the front output shaft on the transfer case it is a large rectangular motor with wires coming out you could use a DVMM to test for voltage to the motor if there is no voltage then you should consider the TCCM under the dash also search the forum on how to check for trouble codes from the TCCM...

 

This may seem like a stupid question, but are all four of tires the same size? If not this could be the problem even if you put your spare on that is not the same size, your 4low will not disengage.

 

This just happened to my wife's 2001 blazer. Dealer replaced the encoder motor. Good thing for extended warrenty. It would have cost $684.00.

Scott

 

I had this happen recently on my 01 blazer. Lucky for me, all I had to do was replace the switch in the dash. Cost me about $38 for the part.