k so i was pissing around with the 4x4 recently, still doesn't want to engage of course. What i noticed here that really caught my attention since this whole 4x4 thing is new to me, was that in 2Hi my actuator is compressing @ all times (2/4hi/low) and i of course not knowing this was out of place never thought about it!


Getting back to the caught my attention - someone posted this same sort of issue and it turned out to be the vacuum switch was the culprit, looking for confirmation that my symptom's suit this issue as well.

4hi/low it will move the jimmy as tho it's engaging, won't engage & returns to 2Hi, all the lights work, didn't have anything flashing on the TCCM diag via pin 13. next step for $20 is the vac switch!

Where's this at? and hopefully a pic or 2 of this plz? i'll reconfirm the TCCM diag tomorrow to be 100% before i sink anything into this part. BTW with the t fitting broken (did this recently and is on my list for tomorrow's repairs) its still pulling on the actuator so i suspect vac pressure is good lol but i have no HVAC control of where it blows to of course.

Am i headed in the right way? anyone got a DIY for this switch replacement? at min any suggestions and tips for this? Think there's any permanent damage done to the 4x4 system since i believe this locks the 4x4 in place (engaged) right?

 

Don't have a picture to send you but the switch is on top of the T-case behind the front druveshaft yoke output. There should be three vacuum lines running to it. This switch seems to be a common problem although I nust admit I have not ever had a problem with either Blazere/Jimmy I have owned.

 

You'll find a diagram on wikipedia

 

gotta link to this diagram? i did a search for it and couldnt find anything with wiki about it other than what gimpy said really.