1989 Digital Automatic AC Problem Need Help
Thread Starter
6th Gear
Joined: Oct 2019
Posts: 6
Likes: 0
1989 Digital Automatic AC Problem Need Help
Ok, I'm trying to diagnose my AC in my 89. When I first got the car 4 months ago the AC worked fine and blew cold I haven't tried it since. Now the compressor clutch won't engage. I have the automatic climate system option, heat works perfectly and when set to the coldest setting it does blow through the AC vents. I checked the AC fuse is and it's fine. I checked the clutch resistance and it came out at 4.4 Ohms. I then checked the other connector voltage and the black/white wire has 9.7V when the AC is on or off. The green wire is at .625V on or off. I also jumped the low-pressure switch with a paper clip to see if it was because of low Freon and it had no effect, the do it yourself AC recharge also had the system in the red showing that it does have pressure if I loosen the quick connect fitting it does release Freon. Freon Bad BCM? What is the correct reading on the black/white and green wire? Is there another way to bypass the low Freon Sensor? My power probe is currently not working so I have yet to force the clutch to see if it works. What else could be the problem?
Last edited by Govinator; Mar 27, 2020 at 08:14 PM.
Drifting
Joined: Jan 2005
Posts: 1,350
Likes: 322
From: San Antonio Tx
The black/white wire should have battery voltage any time the switch is in run position. The green wire is grounded by the clutch relay, which is part of the blower control module on the evaporator housing. There is a delay of several seconds before the compressor is engaged. Be advised, some places advertise these modules as 86-96 but they are not the same. The later modules look the same but do not have the compressor relay. The later modules have the same electrical connectors but are missing pins for the relay.
Thread Starter
6th Gear
Joined: Oct 2019
Posts: 6
Likes: 0
Ah, ok so this is what I would need. The relay for the compressor is separate from the blower motor controller but is inside this same module, correct? Then the blower motor can operate correctly, but the clutch relay part can malfunction separately from it.
https://www.ebay.com/itm/For-1986-19...ke%3AChevrolet
https://www.ebay.com/itm/For-1986-19...ke%3AChevrolet
