AC Problems !

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  #1  
Old 05-03-03, 09:37 AM
conscience4u2
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Question AC Problems !

I have an 88 Toyota Celica GT Coupe. Which has an electronic Air Conditioner Control Panel with “Auto Air” , not a manual control unit that came with some of the 88 Celica’s. I have a manual, 5 speed, transmission and my engine is a 2000 cc. I just recently replaced the Temperature Control Unit with a new one, had the AC compressor checked to make sure it was good and working right, and had the AC charged up with freon. The heating part of the Temperature Control unit works fine. I also have checked all the fuses to make sure there are no blown ones.
When the button is pushed in to turn the air conditioner on, it will come on and work perfectly for a while, the amount of time it stays on and cooling right can vary from between just a few minutes to as long as 45 minutes. When the AC is on and working it blows so cold it will almost run you out of the car. Then the light on the AC button will start to flash and it stops cooling. Once the light starts to flash, I can see that the air is not working and I can definitely feel that it is not cool anymore. I have to push the button again, turning the AC off, then push it again to turn it right back on again to make the AC start working again. So, the sequence of events as I drive down the road are as follows. 1. Push AC button-AC comes on, cools perfectly. 2. Light on AC button starts to flash-AC stops cooling. 3. Push AC button-turning AC off. 4. Push AC button- AC comes on, cools perfectly. Any suggestions and or help with what I can do to fix this will be GREATLY appreciated ! If I have forgotten any info needed, please let me know and I will get it as soon as I possibly can. Thanks in advance ! 4u2
 
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  #2  
Old 05-03-03, 10:54 AM
Join Date: Jun 2002
Location: Long Island, NY
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The light flashing is a fail safe for a/c clutch. It has a rpm sensor in the compressor that sends rpm signal to the a/c amplifier.
The a/c amplifier compares the compressor rpm to the engine rpm. If the two differ by approx 75-100 rpm it sees that as a problem and shut off the clutch and flashes the a/c light.

It uses this system because the a/c belt is shared with the alt. If the compressor was to lock and break the belt, the alt would be lost.

Now the list of whats your problem;

Loose belt

Bad rpm sensor in the compressor(would go open probably when it heats up)

Broken wire from the rpm sensor to the a/c amp

Bad a/c amplifier

Larry
 
  #3  
Old 05-03-03, 11:45 AM
conscience4u2
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Larry,
Thanks SOOO much for the explanation of how things work and what happens. It sure helps me to better understand. Now I'm guessing I need to go through the list you gave me and check each one of them in order. Right ? Thanks for the help and if you can think of anything else please let me know. Judy (4u2)


P.S. I'll make sure to let you know what I find if you want me to.
 
  #4  
Old 05-03-03, 06:29 PM
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Join Date: Nov 2001
Location: North Texas
Posts: 2,345
Larry the Toyotaman

Larry I have been reading your posts and I gota tell ya thumbs up you really know your Toyotas. I having a new 2003 Matrix and having had a 86 Corolla am impressed with you knowledge.Toyota builds a great car for the money however my first year Matrix has way to many dash rattles but thats a diffrent story.
 
  #5  
Old 05-03-03, 07:28 PM
Joe_F
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Thumbs up

Larry is the Toyotaman. Bravo !
 
  #6  
Old 05-04-03, 05:52 AM
Join Date: Jun 2002
Location: Long Island, NY
Posts: 1,531
Thanks

conscience4u2

Forgot one other possible cause is a bad a/c clutch . With the a/c on watch the clutch and look if slips after running for a while. Any thing that causes a speed difference (could even be overcharged, but don't think so in your case blows too cool).


Micheal Van

Their is a TSB for your dash bezel rattle. Their is also a TSB for insulating the upper strut mounts which sounds like a ticking noise in the dash.

Larry
 
  #7  
Old 05-04-03, 06:55 AM
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Join Date: Nov 2001
Location: North Texas
Posts: 2,345
Thanks I will bring it in

Thanks Larry I will bring it in for the oil change and have them fix the rattles now that I know there is a TSB on it.
Keep up the good work Toyotaman.
 
  #8  
Old 05-16-03, 11:03 PM
conscience4u2
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Larry (The Fabulous) toyotaman,
I just spent the last hour posting a reply to the question I had on my AC problems and the site logged me off so when I tried to preview my post I lost everything I had written !! GRRRRRR !!!!
So to cut to the heart of it, I was scared to death to mess with the compressor so I thought I'd check the other things first if I could. I was told (by someone else) I needed to check the Blower Speed Control Relay too. I did and it didn't help.
Next I pulled the AC Amplifier out and saw that it had a black spot on it. Since the thing looked like something that came from the inside of a computer and it was all a bright green color, I thought that might be the problem or at least part of it. So I replaced it and turned the AC on. Now everybody get ready to cheer. Guess what ? The air has worked right since I put the thing back in ! Go Me !! This is the first time in close to a year that I have been able to drive my car and actually have to AC work WITHOUT my having to turn the AC on and off repeatedly !! I am in your debt ! I was scared to death that fixing this thing was going to be way more than I could handle by myself but with your help I did it Thanks soo much for everything ! Judy
 
  #9  
Old 05-17-03, 03:51 AM
Join Date: Jun 2002
Location: Long Island, NY
Posts: 1,531
Glad to help to shed some light on your problem.

Usually the speed sensor and the next a broken wire. Last is the amplifier but I have seen them go bad.

Larry
 
  #10  
Old 05-17-03, 07:02 AM
Joe_F
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Thumbs up

Yay for Larry!
 
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