AC compressor question - ZR-1 Net Registry Forums

mlipmd · 06-04-2021

The '90 Zr-1 I just got probably hasn't had AC for quite a while and the PO told me it was probably just low on freon. When the AC is turned on, the compressor does not go on. It is not frozen, you can turn the inner shaft, but bypassing the low pressure switch connector will not get it to spin. Where can I apply 12V to see if I can activate the clutch? I don't want to fry something and I can't follow the wires coming out of the compressor on the drivers side as they disappear under the plenum. I heard there is a relay behind the battery but haven't looked into there yet.

I connected a can of refrigerant with a valve in the line and the static pressure measured with that, on the low side, was ~50psi with an ambient temp of ~85, so it's probably low on freon. I didn't measure high side pressure because I don't have a gauge set yet. You can't really add freon to the system if the compressor's not running and right now I don't know if the clutch or the compressor is any good. It's getting hot in FL now and I want the AC, but not really wanting to replace the entire system right now, and with everything packed in the engine bay, that looks like a bitch of a job.
Anybody have any suggestions on how I can test the clutch, where I apply 12v to the compressor? Or any other help?
And as an aside, the blower motor runs but very little air comes out of any of the vents. I pulled the blower control module and took a look inside and it's clean as a whistle in there, so that problem may be the vacuum/relay assembly tucked way up underneath the driver's dash.
So in addition to the fun of driving it, I have a new toy to play with for quite a while 'till I get all this sorted out.
I have ordered a FSM but it hasn't arrived yet and you guys know more than that book anyway.

06-04-2021	#1
mlipmd Join Date: Mar 2021 Location: Crawfordville, FL Posts: 216	AC compressor question The '90 Zr-1 I just got probably hasn't had AC for quite a while and the PO told me it was probably just low on freon. When the AC is turned on, the compressor does not go on. It is not frozen, you can turn the inner shaft, but bypassing the low pressure switch connector will not get it to spin. Where can I apply 12V to see if I can activate the clutch? I don't want to fry something and I can't follow the wires coming out of the compressor on the drivers side as they disappear under the plenum. I heard there is a relay behind the battery but haven't looked into there yet. I connected a can of refrigerant with a valve in the line and the static pressure measured with that, on the low side, was ~50psi with an ambient temp of ~85, so it's probably low on freon. I didn't measure high side pressure because I don't have a gauge set yet. You can't really add freon to the system if the compressor's not running and right now I don't know if the clutch or the compressor is any good. It's getting hot in FL now and I want the AC, but not really wanting to replace the entire system right now, and with everything packed in the engine bay, that looks like a bitch of a job. Anybody have any suggestions on how I can test the clutch, where I apply 12v to the compressor? Or any other help? And as an aside, the blower motor runs but very little air comes out of any of the vents. I pulled the blower control module and took a look inside and it's clean as a whistle in there, so that problem may be the vacuum/relay assembly tucked way up underneath the driver's dash. So in addition to the fun of driving it, I have a new toy to play with for quite a while 'till I get all this sorted out. I have ordered a FSM but it hasn't arrived yet and you guys know more than that book anyway.