71 A/C wiring question
Thread Starter
Melting Slicks
Joined: Jul 2009
Posts: 3,264
Likes: 3
From: Vero Beach FL
71 A/C wiring question
Last year I replaced the A/C harness (new) in my 71 project car. I am now getting closer to hooking up the A/C and while doing some testing I found out that the green wire that connects to the compressor is hot even without the A/C switch turned on in fact it is hot without the ignition even on. Any ideas where to start looking? Is it possible that the relay is stuck?
Thanks,
Thanks,
Drifting
Joined: May 2008
Posts: 1,647
Likes: 5
From: Roseville CA
What about when the ignition is on? The AC is enabled when you turn the ignition off to prevent dieseling. It's controlled by the two relays behind the passenger dash. AKA blocking and anti diesel relays.
Last edited by C6DuffMan; Mar 21, 2013 at 06:51 PM.
Pro
Joined: Oct 2006
Posts: 734
Likes: 0
From: Bryan Texas
There is a switch on your ac mode control assembly (or whatever it's called) in your console that juices up that circuit usually. But, there is also an anti-dieseling relay that juices it up when you turn the engine off, it uses the drag of the compressor to help stop the engine. Those would be my main suspects. The anit-dieseling relay should be next to the blocking relay bolted on the air box above the passenger footwell.
Last edited by myk7; Mar 21, 2013 at 07:02 PM.
Thread Starter
Melting Slicks
Joined: Jul 2009
Posts: 3,264
Likes: 3
From: Vero Beach FL
I believe you guys are onto something. I may have plugged the harness to the blocking relay the wrong way (three prongs in a line) or maybe the relay is stuck. I believe that it is getting the power from the horn relay as the blower only works with the ignition on. I am thinking that the only sorce of continued power. It will be this weekend before I can get to the relays to test them.
Thanks for the help I will post the results this weekend.
Thanks for the help I will post the results this weekend.
Thread Starter
Melting Slicks
Joined: Jul 2009
Posts: 3,264
Likes: 3
From: Vero Beach FL
Update
It turns out the the anti dieseling relay terminals were a little corroded. I cleaned them up and the A/C switches all work correctly now. 
Thanks for all the suggestions
Thanks for all the suggestions
