AC Help Needed
Thread Starter
Le Mans Master
Joined: Aug 2000
Posts: 6,273
Likes: 14
From: Austin TX
AC Help Needed
I'm installing a Sanden compressor with r-134 and trying to get the OE system merged with it.
My new wiring harness includes plugs for a blocking relay and anti dieseling relay (GM P/Ns 3996203 and 3996204). I have been told that GM has long since discontinued these relays.
Three questions:
1. What do these relays do and do I need either or both of these relays for an operable system?
2. If I do need them, where can I find them?
3. If I don't need them, how should I modify the wiring harness to take them out of the circuit?
Thanks for any help.
My new wiring harness includes plugs for a blocking relay and anti dieseling relay (GM P/Ns 3996203 and 3996204). I have been told that GM has long since discontinued these relays.
Three questions:
1. What do these relays do and do I need either or both of these relays for an operable system?
2. If I do need them, where can I find them?
3. If I don't need them, how should I modify the wiring harness to take them out of the circuit?
Thanks for any help.
Le Mans Master
Joined: Sep 2000
Posts: 5,635
Likes: 4
From: Orlando Floriduh
Re: AC Help Needed (flynhi)
Some early years used the load of the A/C compressor to stop the engine from dieseling after shutdown by engaging the A/C compressor for a few seconds after the ignition was shut off. This was the function of the Anti-dieseling relay. I'm not familiar with the Blocking relay....
Race Director
Joined: Sep 1999
Posts: 11,360
Likes: 382
From: Plano TX
Re: AC Help Needed (flynhi)
The anti dieseling realy would serve no purpose on your car as with EFI there is no dieseling.
The blocking relay was used so that the full amperage of the AC clutch wouldn't have to go through the small switches in the center console. So you can get any automotive standard relay and use the wire from the center console as the control wire to the relay.
The blocking relay was used so that the full amperage of the AC clutch wouldn't have to go through the small switches in the center console. So you can get any automotive standard relay and use the wire from the center console as the control wire to the relay.
Safety Car
Joined: Aug 2002
Posts: 3,842
Likes: 230
From: SANTA CRUZ CA
Re: AC Help Needed (flynhi)
You might send an email to suncr@pacbell.net. His forum name is SunCr, and he is active in the C4 forum. I don't know if he will read your A/C question in the C3 forum. He is a savy guy and very helpful.
Thread Starter
Le Mans Master
Joined: Aug 2000
Posts: 6,273
Likes: 14
From: Austin TX
Re: AC Help Needed (zwede)
Zwede,
Thanks for checking in. As always, I appreciate your comments. Since I'm really ignorant about this stuff, I have a couple of specific questions in response to your comments.
On the Anti Diesel Relay, could you please look at your 71 wiring diagram and tell me which wires on the ADR plug I need to connect to take this relay out of the circuit. Or do I need to do anything to it?
When I go to the parts store for a relay for the blocking relay, should I ask for a single pole or double pole or what?
Did you make it out to the Raceway for the Lone Star Corvette meet?
Thanks for checking in. As always, I appreciate your comments. Since I'm really ignorant about this stuff, I have a couple of specific questions in response to your comments.
On the Anti Diesel Relay, could you please look at your 71 wiring diagram and tell me which wires on the ADR plug I need to connect to take this relay out of the circuit. Or do I need to do anything to it?
When I go to the parts store for a relay for the blocking relay, should I ask for a single pole or double pole or what?
Did you make it out to the Raceway for the Lone Star Corvette meet?
Race Director
Joined: Sep 1999
Posts: 11,360
Likes: 382
From: Plano TX
Re: AC Help Needed (flynhi)
On the Anti Diesel Relay, could you please look at your 71 wiring diagram and tell me which wires on the ADR plug I need to connect to take this relay out of the circuit. Or do I need to do anything to it?
When I go to the parts store for a relay for the blocking relay, should I ask for a single pole or double pole or what?
Did you make it out to the Raceway for the Lone Star Corvette meet?
