Greetings all,

I recently purchased a 1994 GMC Jimmy 4x4 with the 4.3L VORTEC engine and glad I am back in a Jimmy/Blazer. The beast overall appears to be in could condition and has 177k on the clock.

The Jimmy has some issues here and there but nothing a good tune up and TLC wont take care of.

One issue I have ran across is that it had no heat, which I thought I remedied, due to the fact that the heater core was bypassed..if figured no biggie, just swap a new one in, buy a couple hoses and Im set....well that wasn't exactly the case.

After the heater core repair along with hoses, I noticed that the core did in fact get hot via coolant running through it, but I wasnt getting any heat. I moved the temperature control (its the one mounted with a north and south style control, with fan speed up top mounted east to west).

Anywho, I moved the temperature control and noticed there want much resistance when moving up and down, from cold to hot. Granted, my dad had one of these years back, so I am learning them all over...but if memory serves me correct, there should be some resistance there.

Since I still somewhat had the dash apart, I went to the door behind he glove box and moved the wire and instantly got hot air blowing out. Well half way there I am figuring. I went ahead and unfastened the a/c controls and noticed that someone was in there before me (broken lights and electrical tape). I also noticed that there was a wire down in the dash with a loop on it....i figured that this wire must somehow connect to the temperature side of the a/c control unit.

After a couple moments a examining the a/c control unit, I did take notice of a small peg and placed the wire loop over it. I began to work the control and the door I manipulated by hand was some what moving back and forth, but would not go fully closed in either direction (hot or cold)....she just kind of sat about 75% one way or the other.

Not knowing these units all that well, is it just simply this wire that controls either hot or cold and can it be adjusted?

The right side selector that has the a/c max choices to heater seem to work fine...Jimmy does stumble a bit when I move them fast, but again am curious if this single wire I found control the temperature solely and again can it be adjusted?

When I pulled the a/c unit out a bit, I did notice about 6" up the wire a red metal tab with a hole in it....I was curious if this was a mounting tab that would assist the cable in staying taunt and or true to the path it was designed to reside in.

Id really like to get the a/c functioning the way it should vs leaning over and reaching through the glove box to turn the door and or flapper I have heard them called. Can this wire be cut and adjusted...or does that tab I viewed mount somewhere up in the dash adjacent to instrument cluster?

I didn't know a/c units were so involved with vacuum lines and what not, so I am hoping the stumbling I experienced isn't a ruptured line because I dont know where to begin, nor what tools would be used to diagnose and or identify what needs to be repaired.

If you guys can t offer any suggestions I appreciate it...I know I threw several questions out there which I apologize for, but just want to get the Jimmy up and running again the way she should.

 

Hello all,

Where here is an update.

I started doing some more research on the net and really could not find a picture of the climate control unit so I could start compairing what I had in hand and what it was supposed to look like once installed. I was able to find some pics on eBay of some used units pulled from salvaged cars. Low and behold, that red tab is supposed to slip into a portion of the climate control unit with the hooped metal end of the same cable being secured to the plastic peg for temperature control.

So off I go and try and get this all put back together as it should be, obviously PO was in there or his mechanic and jacked things up a bit. After 45 minutes or so and after shredding my left hands index and middle finger) , I was able to get the unit back together as she should be. Worked the action a couple times an noticed the red tab popped out of place.... serenity now they say.

So I had to pull the entire unit out and man what a chore that is. They dont give you much wiggle room for the blower motor switch, vents selector harness and those darn vacuum lines. Good golly...didn't know it was going to be so involved, but in the end...it'll be worth it.

Finally got it out and inspected the unit further...it appears the red mounting tab should secure and or lock in place within the climate control unit once installed...mine however was broken...no tab. I broke out the Gorilla Glue and unfolded a paper clip giving me a home made wire tie so to speak. Waited for glue to cure and carefully wound the red tab into position via paperclip (theres a hole in climate control unit I went through and tethered again red mounting tab. Gave her a few pushes up and down and I could hear the blend door flap back and forth...so I was thinking success.

Went to reinstall the unit and wouldnt you know it, since the unit is so old and brittle the selector wheel for the vents crumbled in my hand when trying to hook up the vacuum lines again....

I had to order another unit from eBay (hopefully its in good condition) and wil have to report back with either a successful follow up, or another defeat.

Question Id like to ask you folks is, is there any easier way to hook up the vacuum lines to the back of the climate control unit? I am having to wedge my fingers down beneath through the power mirror switch hole to get some access to is and just push and pray I get it on correctly and far enough up on the vacuum ports. Really interested if there is an easier way. The space is tight to begin with and I really dont want to destroy the donor unit that is on its way.

Please advise if you have a trick to it....

 

Hello again...

I didnt receive a response yet, but was able to secure a used climate control from eBay and with some luck was able to hook it up. Again the vacuum lines are a complete PITA, unless I am not seeing an easier way of doing it. The only way I could manage to hook them up was stick my fingers through the power window control switch hole and kind of back brace the line as I finagled getting the unit seated....then came the absolute joy of hooking up the blower speed harness and vent selector harness. There has to be an easier way...so please advise in the event I got to do this all over again. It appears my red tab is missing a portion of it, so I had to use that trusty unfolded paper clip again to tie her somewhat in place.

I still dont have full function of the temperature selection ****...I cant get it to stay on full blown heat or full blown cold, as for the lever creeps a bit towards the middle giving me almost blistering heat, or almost freezing cold air.

Is there a way to adjust the cable at the blend door that sits behind the dash (glove box area). Can it be shortened, lengthened by chance? Im curious if I some how maybe bound up the cable within the dash during my heater core install or yanked on it a bit to hard when pulling the cable loop to secure on the climate control unit.