1995 GMC JIMMY S-Series 4.3 vortec auto 260,000 and still tickin'.


The 3 prong 4x4 switch on my transfer case took a dump and allowed trans. fluid to get into all my vacuum lines, which must have ruined my actuators in my heat controls, along with the 4x4 actuator under my battery. No matter what position i put the control on, it blows heat through the defrost and the floor evenly I guess. Once the problem was diagnosed, I sprayed electrical cleaner into the vacuum system but it did not fix the problem. I thought I had read this B4, but can't remember the remedy. Can anyone give a helpful hand??


ESKY

 

I have read you need to blow the lines out with compressed air but I don't know the sequence. Top to bottom makes sense. I would take the three line connector off the switch. Then start with the top like vacum reservoir, actuator, ect. The thing is you will need to applie the compressed air after the vent T's. You might be able to rig a little nipple on the tube of canned air. I do that cause no compressor.

 

Heater control needs to be replaced after you made sure you've cleaned all the lines of trans fluid. The fluid has ruined the rubber diaphram in the selector switch and most likely the culprit now. Be sure the to clean the lines first because I found out the hard way.

 

Thanks guys. But I already changed the controls....they weren't corrupted with fluid, but where I think the problem lies is in the vacuum diaphram. I think the trans fluid got in there and ruined the rubber diaphram (so I'm thinking) and won't open the lever. I think it was Swartlk that metioned in a thread B4 that it (lever) would automatically go into a mode between both the floor and the defrost, and that's what I think I've got.

If that's the case, how hard is it to get to that vacuum diaphram to replace it. When I shut off the blower, I can hear a vacuum hiss down somewhere under my dash which I'm assuming is that diaphram, because I don't think getting trans. fluid in the system will eat up the rubber lines as much as kill a vac. diaphram, do you??

 

GMC Sonoma & Chevy S-10 Transfer Case Vacuum Switch This guy did kind of a nice job on this, hope you can get to it.

 

Thanks, Spittybays. I do not look foward to the job, but it's going to have to get done, along with a heater core!

 

I have a 98 Blazer with AC and my Temperature controll does not work, it stays on high heat all the time, is there a relay for it. Thanks for any help. Sulley

 

Sulley, you need to start a new ? thread with a title and your info cause no one will see it on the bottom of someones old thread.

 

OK thanks. Sulley