AC Problems - 1991 C4
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Joined: Jul 2014
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From: Portsmouth VA
AC Problems - 1991 C4
Well, the weather warmed up an the AC is not working. My 91 Vette has the automatic climate control system. Here’s what I know and I have done:
- Off button was flashing indicating and error
- Held the air up & down buttons to get to code screen
- Hit the center button and got an error code of 09 - low refrigerant
- System had about 40lbs should have been enough, but pushed it up to 50lb @ ambient outside temperature of 85 degrees
- Reset the system as per owners manual by pulling courtesy light and radio fuses
- The compressor attempted to engage; after a couple of click it stopped
- Checked get 09 error code
- Pushed it to 55lbs and reset.
- Nothing and still get 09 error code
- Swapped gauges to make sure I was getting an accurate reading - gauge readings were identical
- Checked 2 connections at the compressor, I have a good ground and 0 voltage coming to the compressor.
- All fuses are good
Any additional suggestions would be great appreciated. I’m sure I’m missing something simple. Thanks!!
- Off button was flashing indicating and error
- Held the air up & down buttons to get to code screen
- Hit the center button and got an error code of 09 - low refrigerant
- System had about 40lbs should have been enough, but pushed it up to 50lb @ ambient outside temperature of 85 degrees
- Reset the system as per owners manual by pulling courtesy light and radio fuses
- The compressor attempted to engage; after a couple of click it stopped
- Checked get 09 error code
- Pushed it to 55lbs and reset.
- Nothing and still get 09 error code
- Swapped gauges to make sure I was getting an accurate reading - gauge readings were identical
- Checked 2 connections at the compressor, I have a good ground and 0 voltage coming to the compressor.
- All fuses are good
Any additional suggestions would be great appreciated. I’m sure I’m missing something simple. Thanks!!
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Joined: Mar 2015
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Well, the weather warmed up an the AC is not working. My 91 Vette has the automatic climate control system. Here’s what I know and I have done:
- Off button was flashing indicating and error
- Held the air up & down buttons to get to code screen
- Hit the center button and got an error code of 09 - low refrigerant
- System had about 40lbs should have been enough, but pushed it up to 50lb @ ambient outside temperature of 85 degrees
- Reset the system as per owners manual by pulling courtesy light and radio fuses
- The compressor attempted to engage; after a couple of click it stopped
- Checked get 09 error code
- Pushed it to 55lbs and reset.
- Nothing and still get 09 error code
- Swapped gauges to make sure I was getting an accurate reading - gauge readings were identical
- Checked 2 connections at the compressor, I have a good ground and 0 voltage coming to the compressor.
- All fuses are good
Any additional suggestions would be great appreciated. I’m sure I’m missing something simple. Thanks!!
- Off button was flashing indicating and error
- Held the air up & down buttons to get to code screen
- Hit the center button and got an error code of 09 - low refrigerant
- System had about 40lbs should have been enough, but pushed it up to 50lb @ ambient outside temperature of 85 degrees
- Reset the system as per owners manual by pulling courtesy light and radio fuses
- The compressor attempted to engage; after a couple of click it stopped
- Checked get 09 error code
- Pushed it to 55lbs and reset.
- Nothing and still get 09 error code
- Swapped gauges to make sure I was getting an accurate reading - gauge readings were identical
- Checked 2 connections at the compressor, I have a good ground and 0 voltage coming to the compressor.
- All fuses are good
Any additional suggestions would be great appreciated. I’m sure I’m missing something simple. Thanks!!
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Joined: Jul 2014
Posts: 50
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From: Portsmouth VA
Yep... was adding 134a with the car running, AC on full blast and kept putting refrigerant in. I don’t have a the Chevy service manuals (I’ve tried to get a set, but Helms Publications has been out of stock since last Nov.) and the Chilton’s manual is useless when it comes to AC issues. I don’t want to exceed the maximum low-side pressure. The chart with my gauges show 50 lbs should be plenty at 85 to 90 degrees ambient. Anything beyond that is noted with red as excessive. I know that key is getting the compressor to cycle. Once it does, the pressure will go down... and come back up as refrigerant is added.
Any thoughts on how high I can safely push the pressure on the low side, without the compressor cycling, to get the compressor kick on?
Thanks!
Any thoughts on how high I can safely push the pressure on the low side, without the compressor cycling, to get the compressor kick on?
Thanks!
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Joined: Jul 2014
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From: Portsmouth VA
The schrader valve appears good... did the exact same test last night (as I was scratching’ my head) I guess I’ll push a little more refrigerant into the system and see if I can get the compressor come on.
Thanks!
Thanks!
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Joined: Jul 2014
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From: Portsmouth VA
I think you’re right Gear Jammer. When the light is flashing, the compressor will not run. I reset it by pulling the radio and courtesy light fuse, start it set the AC on high and get a little coolant in. The compressor will run in very short cycles and then stop. I go back through the reset and try to get a little more in. The cycles seem to be getting a little longer but it keeps erring out. I believe part of the problem is the heat. It was 95 degrees out. The freon can was getting so hot, I couldn’t hold it... did the back and forth hand dance. Yeah... short hose.
Any suggestions? Any one?
Any suggestions? Any one?
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From: Portsmouth VA
It was simply the fact that is was 95 out, the hose was short and the radiator fan was blowing hot air right on my hand and the can. Its not a quick process... but yeah, with the can under pressure, adding heat like that is not good at all. Thought about using and empty Folgers container and putting the coolant can a water bath... but it just got too dark. And I have to admit, I was getting a little pissed off. That’s when you just need to walk away for a little while.
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It was simply the fact that is was 95 out, the hose was short and the radiator fan was blowing hot air right on my hand and the can. Its not a quick process... but yeah, with the can under pressure, adding heat like that is not good at all. Thought about using and empty Folgers container and putting the coolant can a water bath... but it just got too dark. And I have to admit, I was getting a little pissed off. That’s when you just need to walk away for a little while.
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From: Portsmouth VA
Did you have to keep resetting the system to keep the error light from flash? Once it starts flashing, the only way to get the compressor to cycle is to stop, pull the fuses, reset and start over. Working alone, you’re going back and forth. There seems to be a correlation between the compressor stopping cycling and the error light flashing.
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From: Portsmouth VA
Long story short... 1991 Vette that I’ve has less than a year. Just turned 28K miles. But damn... full of little bugs that I’m slowly getting on to of... but the wife IS NOT HAPPY. 
I had a 78 Silver Anniversary Vette that went down the same path and had to sell it to keep peace at home.
The can piercing valve on my big set of manifold gauges is leaking and I was using one of the 12-inch low-side connectors.
I will prevail. This forum has been very helpful.
Thanks! I let you know how it goes with round 3
I had a 78 Silver Anniversary Vette that went down the same path and had to sell it to keep peace at home.
The can piercing valve on my big set of manifold gauges is leaking and I was using one of the 12-inch low-side connectors.
I will prevail. This forum has been very helpful.
Thanks! I let you know how it goes with round 3
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Did you have to keep resetting the system to keep the error light from flash? Once it starts flashing, the only way to get the compressor to cycle is to stop, pull the fuses, reset and start over. Working alone, you’re going back and forth. There seems to be a correlation between the compressor stopping cycling and the error light flashing.
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Joined: Jul 2014
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From: Portsmouth VA
That’s what I’m afraid of. I’ve never had issues like this with the system in my other cars. Its even harder without a FSM... Helms has been out of stock since last November.
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From: Cave Creek arizona
First I set the AC on max cool (recirculate) then set it at 60 the lowest temp. The FSM might even say to press the lower the temp button after you set to 60 but I can't remember for sure. Once I did that I puled the fuses to reset and then immediately started the recharge after restarting the engine. The compressor continued to cycle as I added 134 until it ran 100% of the time once I had enough 134 in the system. I am traveling but if I can figure a way to copy and paste the info from the FSM I will send you a PM.
Did you have to keep resetting the system to keep the error light from flash? Once it starts flashing, the only way to get the compressor to cycle is to stop, pull the fuses, reset and start over. Working alone, you’re going back and forth. There seems to be a correlation between the compressor stopping cycling and the error light flashing.