C4 1992 climate control not changing blower speeds
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Joined: May 2005
Posts: 71
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From: Tampa FL
C4 1992 climate control not changing blower speeds
I had my mechanic repair my AC, turns out the original AC compressor had gone bad and he put in a new $1400 warrantied kit. Quite honestly, I just don't have the time to do this stuff anymore. Regardless, for the AC, it was time. It had been losing coolant and was needing to be recharged more and more often.. So, just before the replacement, even though I wasn't getting any AC the my climate speed control (1 - 10 blower level) was working - it was blowing low warm air (setting 1) all the way up to high warm air (setting 10). Now after the change, its only blowing at one constant speed - and even though visually the digital display is showing speed going up and down (1 - 10), the actual blower speed won't change regardless of what speed its actually set to. The temperature control is working - just not the blower speed.
On a side note, the digital display now goes down to 0 - after 29 years of owning this car, I swear it only went from 1 to 10, I never recall it being able to go down to 0 (zero). Maybe that's an insight into something....either into the problem or its a sign of my deteriorating mental capacity to remember things.
My mechanic says its one of two parts - the controller head or the programmer, but due to lack of diagnostic codes is unable to determine which one. He did test the blower control module and says its good and then replaced it just to make certain, but the problem still persists. But unfortunately, he always says its quite possible to have to buy first part...and if that doesn't fix it then buy second part. But you can't return the first part. For electronics on "these older cars", its a one way purchase - no returns. Logically, one would think "it worked when I brought it you...you must have done something wrong". But too often I have seen parts dependent on one another that when one fails or is changed, the other one suddenly no longer works. Its like the two original parts had a toxic, but functioning relationship - when part is changed, the relationship fails.
I called another shop that works on Vettes, too far away and too expensive for me to regularly go to and they indicated it is most likely the blower module - that even though its working, its not working correctly, especially since the control head digital display still shows going from 1 to 10 and back down again.
Anyway, I have been going to my current mechanic and his quite trust worthy, and often saves me bank over what anyone else in the area chargers. I have to come to simply trust what he says. However, because he is not a vette specialist, I am posting my questions here in hopes that I might be learn and provide him a list of "likely causes" that might better guide him to the root cause and possibly save me money.
1. What are the first things I should be looking at?
2. In this scenario, what is most likely the cause?
On a side note, the new AC compressor is like an artic blast compared to the original one....i guess the original one was dying a slow, slow death and I had just gotten used to "not as cold" or "takes a while to cool down" or "is that air cold or is just not as warm as the outside air". LOL. Either way, living in FL having a fully functioning AC is a must.
On a side note, the digital display now goes down to 0 - after 29 years of owning this car, I swear it only went from 1 to 10, I never recall it being able to go down to 0 (zero). Maybe that's an insight into something....either into the problem or its a sign of my deteriorating mental capacity to remember things.
My mechanic says its one of two parts - the controller head or the programmer, but due to lack of diagnostic codes is unable to determine which one. He did test the blower control module and says its good and then replaced it just to make certain, but the problem still persists. But unfortunately, he always says its quite possible to have to buy first part...and if that doesn't fix it then buy second part. But you can't return the first part. For electronics on "these older cars", its a one way purchase - no returns. Logically, one would think "it worked when I brought it you...you must have done something wrong". But too often I have seen parts dependent on one another that when one fails or is changed, the other one suddenly no longer works. Its like the two original parts had a toxic, but functioning relationship - when part is changed, the relationship fails.
I called another shop that works on Vettes, too far away and too expensive for me to regularly go to and they indicated it is most likely the blower module - that even though its working, its not working correctly, especially since the control head digital display still shows going from 1 to 10 and back down again.
Anyway, I have been going to my current mechanic and his quite trust worthy, and often saves me bank over what anyone else in the area chargers. I have to come to simply trust what he says. However, because he is not a vette specialist, I am posting my questions here in hopes that I might be learn and provide him a list of "likely causes" that might better guide him to the root cause and possibly save me money.
1. What are the first things I should be looking at?
2. In this scenario, what is most likely the cause?
On a side note, the new AC compressor is like an artic blast compared to the original one....i guess the original one was dying a slow, slow death and I had just gotten used to "not as cold" or "takes a while to cool down" or "is that air cold or is just not as warm as the outside air". LOL. Either way, living in FL having a fully functioning AC is a must.
Last edited by rolinger; Sep 15, 2021 at 10:01 AM.
Instructor
Joined: Aug 2016
Posts: 188
Likes: 40
From: Rockaway NJ
I had a similar issue on the control head of my 94. The fix was to remove the control head, dismantle it and clean all the contacts with a pencil eraser. It’s low tech but my control head has worked fine ever since. It’s a pretty easy job.
Navigator
Joined: Jul 2014
Posts: 9
Likes: 0
From: Hillsborough NJ
Similar- issues and more. Most buttons did not work and A/C would cut on and off (cold air then heat)--had A/C system perviously serviced because I thought it was low freon. --evacuated and coverted to new freon -- not too expensive --less than $150.00. No Succes-- Followed Ozzstar's on YouTube
to dismantle and clean all contacts. Follow all steps carefully--a short afternoon of work, Everything fine now. Thanks Glen at Ozzstat's . Will take it out for a long drive tomorrow becasue prior on long rides >50 miles when running A/C in previous On /off issue and most button not working-- engine would start to run rough, stall and not restart. Had to wait about 30 minutes and it would start right up.
