ok here it is ive got a 1993 s10 blazer 4.3 vortec. my 4x4 stuck on i replaced the encoder motor lost powerto the encoder,and had to do the battery reset thing. it got the power back and four hi work fine now but wont go into 4 low. light just blinks any ideas would be appreciated i think the tccm is working it clickes for for hi but not sure? how can i reset the tccm?

 

I don't know how to reset the TCCM, but an idea is to check all of your vacuum lines. the whole system is vacuum controlled (which kinda sucks) and if there is a leak anywhere it will only partially work. Oh, and when you're checking them don't forget the three lines that go down to the transfer case, they have a habit of being eaten away by standard driving and they'll melt if they get too close to the manifold.

 

agreed start with vac lines last winter my 94 did same thing lights would blink but that was it turned out had a bad vac line at the actuator (under the battery) I just replaced all my vac lines while i was at it for good measure 4x4 has worked flawlessly since.

 

If the 4W HI is engaging then your 4W low is not a vacuum issue. I believe the Vacumm lines are for the Actuator only. That locks in the same for 4W Hi or Low.