AC Help Needed

[Eyeorg]

A few weeks ago I tested the AC in my new to me FJ60. It blew Ice cold, and for a few days we enjoyed the cold air, and then i traveled for a bit and the temps werent as hot so I didnt need it. Fast forward a few weeks, and I replaced all the LED's in my dash, and the center console including the AC light as it was not working previously.

Now I have no cold AC, its just all hot all the time in my 90+ degrees heat here in Utah.

Without reading my past posts, you should know I dont know much about cars, but I am working on it and for that I should get some credit. So temper your answers a bit.

My questions:
1. Could my LED replacements have any impact on this? Seems unlikely, but i dont like coincidences. I only see a single cable coming out of the AC button, and it appears to be plugged in as expected.
2. When I push the AC button in, it turns blue. Should I see something happen under the hood at the compressor? It is belt driven, and that appears to work, but shouldnt the front of it be spinning when the AC is on?
3. Id love to fix this myself, but have plenty of other jobs Id rather do like rebuild the knuckles. Should I just buy a new compressor or circuit board, or what is the easiest way to troubleshoot/fix in your opinion. I do not have the tools to measure pressure.

 

[TRAIL TAILOR]

If you disconnected AC button switch from the main harness when you changed bulbs... Make sure it is plugged back in correctly and seated.

Does the blue AC button light up when engaged?

 

[OSS]

The AC compressor turns on by a magnetic clutch integrated into the front of it. I think there’s 2 black wires running out of it.

When 12V is applied to those wires (12V+ on one wire and 12V- on the other) the electromagnet energizes and clamps the pully so that the belt will spin the compressor. It’s really simple.

So yeah - when the Blue AC button on the dash is pushed, the AC clutch should close and make an audible click - and the compressor should then spin.

You can test the function of the AC clutch by disconnecting the 2 wires coming out of it and applying battery voltage to them. + and - It doesn’t matter which of the two wires you apply the 12V+ to. The magnetic clutch doesn’t care. Either polarity is fine.

If the ac magnetic Clutch is working properly, you’ll see the clutch disc clamp and you’ll hear it when applying voltage.
This test can be done with engine off.

 

[TRAIL TAILOR]

Also, if there is not enough pressure in the system the compressor will not engage. Sounds like a leak if it worked previously.

Go have it tested again.

 

[Eyeorg]

If you disconnected AC button switch from the main harness when you changed bulbs... Make sure it is plugged back in correctly and seated.

Does the blue AC button light up when engaged?

I never disconnected it, just replaced the bulb, but i had thought maybe I accidently disconnected something I wasnt aware of.

It does appear this wire is connected correctly, and the bulb does light up blue so I assume its not the issue. Ill cross that off the list and put the dash back together.

The AC compressor turns on by a magnetic clutch integrated into the front of it. I think there’s 2 black wires running out of it.

When 12V is applied to those wires (12V+ on one wire and 12V- on the other) the electromagnet energizes and clamps the pully so that the belt will spin the compressor. It’s really simple.

So yeah - when the Blue AC button on the dash is pushed, the AC clutch should close and make an audible click - and the compressor should then spin.

You can test the function of the AC clutch by disconnecting the 2 wires coming out of it and applying battery voltage to them. + and - It doesn’t matter which of the two wires you apply the 12V+ to. The magnetic clutch doesn’t care. Either polarity is fine.

If the ac magnetic Clutch is working properly, you’ll see the clutch disc clamp and you’ll hear it when applying voltage.
This test can be done with engine off.

Yes the clutch doesnt seem to be engaging, as the compressor doesnt seem to spin, I swear previously i saw it spinning, so this seems like the issue to me.

By "testing" this, can i use any type of wire? I know that sounds stupid, but i dont have wire hanging around.

 

[Eyeorg]

Also, if there is not enough pressure in the system the compressor will not engage. Sounds like a leak if it worked previously.

Go have it tested again.

I guess i will try this if the magnetic clutch works when I test. thanks

 

[Eyeorg]

Yes the clutch doesnt seem to be engaging, as the compressor doesnt seem to spin, I swear previously i saw it spinning, so this seems like the issue to me.

By "testing" this, can i use any type of wire? I know that sounds stupid, but i dont have wire hanging around.

OK i realized that was a stupid question. Found some 14-2 romex i had laying around, stripped the ends, put the + and - on the battery and then hit it with just the + cable, as there was only 1 wire coming out of the compressor, and presto I heard the clutch and saw it pull in.

So i guess that works. Now something is making it so that it doesnt engage. I guess it could be low pressure? Anything else I should check before I take it in?

 

[yotadude520]

Just read your post - check your freon levels and check power to the compressor via the below:

Turn the A/C on full blast, unplug the wire going to the compressor and put a testing lamp in it. If it lights up the amplifier (computer) is sending power to the compressor. If it does, take an alligator clip and connect it to the compressor end and hold it on the positive terminal of the battery. If there is power to the compressor and it is not spinning I would guess your clutch has seized.

If the test lamp does not light up and the system was working previously, your amplifier could have stopped working, or you ran out of freon due to a leak and the low pressure switch is doing it's job. I would suggest hooking up gauges on the system to see if it's still charged and if there is an adequate amount of freon, you might have a bad amplifier.

 

[Eyeorg]

Turn the A/C on full blast, unplug the wire going to the compressor and put a testing lamp in it. If it lights up the amplifier (computer) is sending power to the

Thanks dude, great idea Ill test this next

 

[Skreddy]

How long ago did you buy it? Was the ac working right after you bought it? The seller could’ve just charged it up with an AC Pro can or something to get it working for the sale.

 

[vipergrhd]

What refrigerant is in your system? R-12 or R134? You may have a leak if all of a sudden you lost your A/C, best thing to do is find a shop that still works on R-12 if that's what you have or rent a gauge set if it's R134.

 

[Eyeorg]

What refrigerant is in your system? R-12 or R134? You may have a leak if all of a sudden you lost your A/C, best thing to do is find a shop that still works on R-12 if that's what you have or rent a gauge set if it's R134.

I have no idea

 

[Eyeorg]

How long ago did you buy it? Was the ac working right after you bought it? The seller could’ve just charged it up with an AC Pro can or something to get it working for the sale.

I bought it last October, and i didnt need AC until spring. So i didnt check it. The heater didnt work, so I fixed that during the winter. Yes I have to imagine that it was probably a temp fix, there definitely were other areas that had similar temp fixes. Ill try to see if i can validate if its getting power, and if all works as expected then i will take it in for pressure testing. I may go without AC this summer if thats the case

 

[Eyeorg]

@yotadude520 - I disconnected the cable, turned on the AC and put a testing light on the wire, nothing happened. I then bypassed that and put a wire directly from the battery + to the compressor, it turned on and then the air started to get cold in the car.

I didnt let it run long, but could I run it this way temporarily until I can get it fixed.

Is this a circuit board problem?

 

[RodrigzCrzr]

Check your connections Underneath the dash. make sure the thermistor is connected. And everything else.

 

[Eyeorg]

Anyone willing to tell me how i can find the thermistor? Maybe a general direction using this pic?

I checked the voltage on the amplifier and it looks like my thermistor input is not working, so I am trying to track that down, or maybe bypass it to see if its the problem?

 

[RodrigzCrzr]

It is in that big box. Where the expansion valve is at.
Wiring should be at the connection of that big box and the heater box on top.
It is more towards the firewall inside the box.

 

[Eyeorg]

It is in that big box. Where the expansion valve is at.
Wiring should be at the connection of that big box and the heater box on top.
It is more towards the firewall inside the box.

OK so I have to open the box up then to get inside. Thanks

 

[RodrigzCrzr]

OK so I have to open the box up then to get inside. Thanks

Yes

 

[yotadude520]

Hold on a second - before you start digging into your evaporator (which requires all the Freon to be removed) read the below thread, you can also bypass the amplifier completely by running a cotter pin to pins 3 & 7 which will allow you to control power to the compressor by pressing the A/C button on the dash. Not ideal, but I ran my 87 pickup that way for years, you'll know when the evaporator freezes as it will start to blow warm air.

The A/C Amp Thread

forum.ih8mud.com

My guess is you've got a bad A/C amplifier or you need to adjust the knobs to get power to the compressor.