1996 Toyota Coralla AC question

188k, the car has been flawless until now. While driving the ac started to blow warm and the light that comes on when the AC is running is now off.

I checked the relay under the hood and it is fine. I went to Autozone and installed a new one; there was no change.

I purchased an AC refill kit, complete with gauge. I reasoned that there could have been a loss of pressure and the AC turned itself off as a preventative measure against damage. When I checked the pressure, the gauge shot over into the red area. 110lbs if I recall.

Looking closer at the compressor, it appears a tar-like substance was flung onto the radiator. Some of this substance appeared to be on one of the hoses too. Maybe a hose burst? Then how is there not only pressure, but too much pressure?

The AC compressor will not kick on and there is what appears to be excess pressure and a black substance. Any ideas on what may be going on?

Re: 1996 Toyota Coralla AC question

Pressure of freon is relative to the temp. If the temp goes up, so does the pressure. I'm not a wiz on automotive since that is not my specialty. However, all systems have the same basic safety devices.

There should be a high pressure cut out switch and a low pressure switch. Some cars have a switch that shuts off the clutch when the engine is calling for all its power.

The very first place I check on any A/C unit that I work on is the condition of the condensor coil. That would be the one that is located in front of your radiator. If it is compacted with road debris and cannot allow the freon to condense into a liquid, the high pressure switch will keep the clutch from kicking in. A clogged condensor will cause the pressure to increase. Compressing the freon makes it real hot and must be cooled to condense in into a liquid. The hotter the gas is, the higher the pressure is.

Run cold water over the condenser and then try turning the unit on. If it kicks in the clutch, then you have a real dirty condensor. To really diagnois the problem, you should have a regular manifold set of guages to actually know whats going on both sides of the system.

Since your light is off, check the fuses. A fuse is not the same thing as a relay. Your problem maybe more of a electrical problem vs freon problem. A test light and or meter would be a big help. If your not getting voltage at the wires of the compressor, then you have an electrical problem. Could even be the function switch for your heat/a/c modes. Good Luck//////SS

Re: 1996 Toyota Coralla AC question

Thanks for the advice. I got a buddy who knows his way around electrical systems, and he said he'd get his voltmeter out and check that first. The condensor is clean and has nothing blocking air to it, so I doubt it's that.

Thanks!

Re: 1996 Toyota Coralla AC question

Silly question... which connection did you connect your gauge to? I'm sure you know this, but there is a high side and a low side (it should only connect to the low side, but it was a thought). I had a similar experience when I was charging the system in my dad's 94 Toyota truck. At first, the gauge went straight to the red zone, but then it sucked the coolant down and started behaving. Did you have the A/C on when you were doing this? If the car was off, the pressure will be sky high. Go back and re-read the instructions on your refill kit and make sure you didn't miss anything. I hope this was helpful!

-Carl

Re: 1996 Toyota Coralla AC question

The compressor won't come on at all. I was hoping the pressure would be zero and the introduction of coolant would make it come one, but that was not the case. I did have the gauge hooked to the low side.

I'm beginning to think it's electrical and something is not kicking the compressor on.

Re: 1996 Toyota Coralla AC question

The compressor wasn't turning on in the truck either, it took some coolant to get it to turn on. Wiggle the connector a bit to make sure it's completely connected... now that I think about it more, I think that may have been part of my problem. Make sure it's completely connected! I was working on it in a parking lot, in ridiculous heat, so the details are a little fuzzy. I almost gave up! Your theory may indeed be correct, but I'd give it another try (maybe when the friend is there to do the rest of the troubleshooting). It was such a moment of triumph when the cold air started blowing!

Re: 1996 Toyota Coralla AC question

I'll do that this weekend. Thankfully the car is somewhat of a back-up vehicle. I have a Dodge Ram that sucks gas like you would not believe, so I try to drive the Toyota during the week. However, it's 104 degrees here in good ol' Dallas, so I'll pay to gas the truck up if it means cold AC!

Re: 1996 Toyota Coralla AC question

I hear you on that one... We (the S.O. and I) just moved to Georgia from Indiana.. and it's HOT (although not as hot as Dallas)... we drove my gas-guzzling monster van for the first week and a half until I could sort out the A/C issues in her much smaller, much more efficient Solara. I wish you luck!

Re: 1996 Toyota Coralla AC question

if you will find your low side switch and unplug it and jumper the wire side of the plug together you compressor should kick on. then you pressure on your gauge will go down, and you will probably have to add a can. your low side pressure will show high when the compressor is not running. had a dodge truck today that compressor wouldn't kick in. tripped out my guage, freaked me out for a second till i realized the compressor wasn't running, jumped the low pressure switch, pressure dropped to 20 lbs. added to cans, burr, it was cold.

Re: 1996 Toyota Coralla AC question

Jason, I'd listen to Rev...Sounds to me like he's got more experience with A/C than I do.... (I'm no expert).... I was lucky enough not to have to go through that, and if your system plays nicely, you'll be all set. If not, try jumping the switch. I love this forum, I learn new stuff every day!

Re: 1996 Toyota Coralla AC question

Okay, I'll try this a second time! Hey all, first post. Did you check the belt that drives the compressor? I once owned a '92 Toyota pick up with an AC that would start kicking the compressor on and off and blow hot air. It would start out cold and then you could hear the compressor switching on and off and it would then blow hot air. Turned out it was a worn belt. Changed it and it ran flawlessly after that.

Re: 1996 Toyota Coralla AC question

The belt is fine; good tension and all. It's fairly new too, as I replaced all the belts a couple years ago.

I'm trying Rev's trick this weekend. Sound like a simple way to get the compressor spinning. I know exactly where the low side switch is too.

Cheers Rev, appreciate the advice!

Re: 1996 Toyota Coralla AC question

not a problem jason, i deal with that kind of stuff everyday. need anything else you can contact me directly at www.oklahomabikerwedding.com

Re: 1996 Toyota Coralla AC question

Be sure to check ALL your fuses paying special attention to the a/c fuses and gauge fuses. You car has an a/c amplifier which controls the a/c compressor. It also sends a signal to the Engine Control Unit (ECU) for idle speed control. It receives signals from the pressure switches on the refrigerant system and there is also a revolution sensor on the a/c compressor that inputs to the amplifier. The amplifier is also the triggering mechanism for the a/c relay. The wiring of your system is fairly complex and not for the DIY.