My AC is not coming out cold...because the compressor is not engaging. I have had this problem before.

Last year I took the car to have a tail pipe hardness welded. As I drove home I stopped by a friends house for a visit...Then I noticed that my ALT gauge was getting weak, so I went straight home. I exchanged the ALT (have an extra) and the problem didn't go away. The next day I was going to the auto parts store and it was raining. I had the AC to try and defrost the wind shield and all of a sudden the compressor engaged and the AC started to kick-out cold. The ALT gauge went back to normal and was glad because I had cold air.

Now here'* what I think happened: Because they grounded the welding machine onto the car frame this caused a problem to the compressor (hence low ALT reading) which then caused it to engage allowing the pulley to work correctly. It'* wierd, but I ended up with cold air.

I have noticed in some forums that state: hotwiring the high press cutout switch (close the circuit) How would I do that, and is that the electrical plug located on the compressor :?: Does anyone know any other tricks that might help to kick start the compressor, please reply with details. Would tapping the compressor with a hammer (like the starter when not engaging work) :?:

Please help, thanks

The compressor isn't engaging for a reason. That reason is that the system is low on refrigerant.

The only reason you'd want to by-pass the refrigerant switch is to get the compressor to kick on to accept refrigerant.

Yes, you do have the location identified....pull the black boot off the top of the compressor (it'* on the side) and complete the loop with some alligator clips. You'll hear the compressor kick in... Have your refrigerant ready to add to the system once it does kick on.

The plug going into the big silver tank looking thing with the lines coming out of it on the firewall... pull the plug and take a paperclip and connect the 2 ports together. see if that kick starts your compressor.... if it does.. your switch is bad.

NO...if it does, then his switch is GOOD. The switch is doing what it should be in that case. The purpose of that switch is to not allow the compressor to engage when the refrigerant is low.

Would I put a paper clip on the connection plug with wires or the connection on the compressor :?:

if u want u can come by my house and i can use the scan tool on it and see if i can engage the compressor

Into the plug with wires.

Bypassing the high press cutout worked for mum because he had just had the car recharged with 134a and had high pressure.

Well if you have good pressure of ref. in there it would be okay to use this method then eh?

Well, if the pressure was adequate to begin with, the switch wouldn't have to be jumped out. The purpose of jumping the switch is to get the compressor to engage so that it will accept refrigerant when attempting to charge the system.

If you just try adding R12 or 134a to system that has a compressor that isn't engaging, the refrigerant isn't getting into the system. Jumping those two wires, will engage it, allowing refrigerant into the cooling system.