Help me fix my A/C. Clutch is not engaging.

[TonkaTom]

Title says it all. The car is a 1989 sr5
The electric A/C clutch is not engaging when I push the button on the console. So I looked under the hood to see what was what and I found this wire which was slightly exposed:

I believe that that is the A/C clutch wire. The one with the fray in it is the power and the other is the ground just for info. I initially thought that this was the problem but so I carved a bit of the rubber away under the electrical tape there and tested for continuity which was good. So this area is not the culprit. I also thought that the compressor would be the problem since it has not worked for a while so I unplugged the above plug and applied 12v directly to that plug and the clutch kicked in. So there is a problem getting the signal through. When I push the button in the cabin the light also comes on so I think that it is still good. I also checked the fuse in the passenger kick panel and it was also good and surprisingly pristine looking.

Back to the button real quick. If it could be the problem despite the light coming on just fine when I push it, is there any way to get to it to test it without removing the instrument cluster. I looked today just in case and it looks like I will have to remove the entire dash. I do not want to do this, so if there is a better way please let me know pictures also helpful.

The blue plug in this next picture goes to some part of the A/C system but I don't know what. Some clarification here would be helpful as well.


So my question for you guys is not what should I do next?

EDIT: If anyone needs other/different pictures I can run out and take some more.

[90 GP]

There is a pressure switch in the vicinity of the metal line in 2nd pic that has a black electrical plug attached to it. If freon level is low it prevents clutch from cycling to prevent damage to compressor. Has the system ever been converted from R12 (the original factory fill freon) to R134? If it has you can buy a can at an auto parts store ,jumper the connector and refill. If not a retrofit with a complete evacuation and refill and new connectors to adapt it would be necessary. The R12 and R 134 are incompatible.

[90 GP]

If you want to verify if the pressure switch is the cause of clutch not operating here is a link for the electrical circuit . Also there are fuses behind passenger side kick panel including a resettable relay for blower.

http://opc.mr2oc.com/online_parts_ca...CorollaFWD.pdf

[TonkaTom]

Thanks, I forgot to mention that it has been updated to r134. I went to fill it up the weekend before school, and it did not come on, but when it did work it was not very cold. So it could very well be that the pressure is too low...

[TonkaTom]

I don't really understand the A/C system, but doesn't it have to be on in order to pressurize it?

[90 GP]

The clutch has to be engaged and compressor running to charge the system. Could probably hook up your charging hose and can to charge port and jumper the pressure switch to allow a/c to run and then open valve to allow R134 to enter system

[Donald]

You should be able to get enough static pressure into the system so the switch will activate the clutch.

You can start charging the system with everything turned off, get some pressure in it, stop charging, and then turn the system on, and continue to charge.

If you do a static charge, and the clutch still doesn't work, you might have something else wrong other than low pressure.

[TonkaTom]

Thanks guys. It was the low pressure switch. I warmed the car up and ran a bottle of refrigerant and stop leak and the clutch kicked in within seconds of plugging the bottle in, after over a year of not running it. I then added another bottle of just refrigerant and now it is quite cold.
Thanks a lot. I didn't know about that switch earlier.