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Discussion Starter · #1 ·
Hello All,

I am looking for help from people who are experts or very familiar with the Air Con electronics of the Supra. I would like to resolve this problem before the summer comes along again and the hot so cal heat melts me!

My AC is very fickle. But just some background on my car before I start. It just went through a major restoration with all new mechanicals. Newer (used) JDM engine, new belts and gaskets, A Brand new engine harness (cost more than the stupid engine, didn't want to chance it). New starter, alternator, water pump. New clutches, U joints. The corners has new shocks, springs, calipers, roters pads and brake lines. The AC system has all new freon lines and an evapourator. The cooling system has all new hoses, Koyo radiator, heater control valve. In essence, over 90% of anything mechanical that is on the car has been refurbished or replaced.

With that note, the car doesn't overheat and the freon does not leak. (dye tested three times!) It has been retrofitted with R134A. I know it is not as efficient, but R12 is getting rare and expensive.

Here is my question...

The AC blows very cold when the compressor clutch kicks on. The AC doesn't work when it doesn't kick on, despite me having turned on the AC. The engine could be cold and it could still not work.

I touched the clutch connection in the engine bay to the battery to see if it would work, and it engaged every time. Just as I was about to hard wire a clutch on off switch into the car, it came back on and I noticed something. My dash clock is on and my cigarette lighter charges up my phone.

So I observe a few more days, and I notice that when the dash clock and cancer stick lighter works, the AC compressor clutch kicks on as well. If the clock and the lighter DOES NOT work. then the AC no work either. And the item work when they feel like it and not when they don't

Any ideas? Please. No responses on leaking freon or the car overheating. I have already addressed those issues. Thanks. Much appreciated.
 

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Question to suit.
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3,562 Posts
My a/c clutch went bad, but "sometimes" worked. I just replaced the whole unit and it was better. Good luck man.
 

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Discussion Starter · #3 ·
Thanks. That is a last resort since so far it has worked every time I hard wire it to the battery. I know it's an electrical issue that is connected together. Any more advice?
 

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Some Guy With A Supra
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u replaced the a/c clutch??? how much does that go for, cuz i'm having the same symptoms with my 87t. Only works some of the time.
 

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The 15 amp CIG fuse also feeds the magnetic clutch relay for the A/C. It also feeds the super monitor(clock) and the Anti theft computer.

You might want to check the ground. A bad ground might be an intermittent problem.

THT Dennis
 

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Discussion Starter · #6 ·
Yes! Someone has been paying attention. Thank you very much for the advice. The ground was actually fine. After actually reading the manual and looking at the fuse, some doofus (not me) had a 7.5A fuse in place of where the 15A fuse should have been. I replaced it and immediately the clock turned back on and the cigarette lighter worked again!

But the clock stilll occasionally turned off when I was drawing power to the cig lighter. My HKS turbo timer read the voltage to be 11.71 volts. Too much load? I replaced the fuse again, and I tried to draw power to the cig lighter to see if the clock turned off, and I couldn't. Well I will try when I am actually driving the car. But I find solve this problem once and for all.

Thanks for your help Dennis (crafty) Much appreciated. Hopefully the stupid clock will continually stay on. (This begs, the question, why the hell did Toyota run the clock, cig lighter and ac clutch on the same circuit? geez...)
 
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