A/C Question
A/C Question What up guys, I need to know how to do this cause this is driving me CRAZY!!! I have a 3rd Gen camaro and im going to use the 3rd gen A/C compressor (F-Bodymotor sport makes a bracket for that) rather than the 4th gen one. How do i hook up the wires so the computer knows when the A/C turns on and also to turn on the cooling Fans.. Does this all make sense?
You need two things to make the PCM control the A/C .. The first is the clutch control from the PCM, which goes to a relay and then to the compressor. The second is the pressure sensor (3 pin connector), which goes in the liquid line right before the orifice tube. Depending on how your plumbing is laid out, you can add the sensor schraeder valve yourself or it may already be there...
and your talking about using my old A/C compressor right? I need to add another sensor in the line to make it work right? Doesnt the 3rd gen compressor already have the pressure sensor on it?? I didnt think it would be this hard at all. LOL. I guess what im trying to say is im trying to use my old lines, compressor, and A/C circuit somehow tied into the LS1 harness. Help me out Brains, I feel like you could give me an answer to my sleepless nights LOL!
New or old compressor doesn't matter -- they both only have two wires 
The only variable is going to be the pressure control. I'm not sure the specifics of the 3rd Gen setup, or more accurately whether or not the 3rd gen was computer controlled. If its NOT computer controlled (ie. uses a pressure switch to cycle the compressor) then you change nothing and it all magically works. If it IS computer controlled, then follow what I said above. Maybe someone more familiar with the 3rd gen setup can chime in
The only variable is going to be the pressure control. I'm not sure the specifics of the 3rd Gen setup, or more accurately whether or not the 3rd gen was computer controlled. If its NOT computer controlled (ie. uses a pressure switch to cycle the compressor) then you change nothing and it all magically works. If it IS computer controlled, then follow what I said above. Maybe someone more familiar with the 3rd gen setup can chime in
According to the 89 Camaro wire diagram on computer control, The computer only has an A/C on Input which goes to the A/C Press switch, I dont think the computer controls it though?? The part that im confuse about is how to tell the LS1 ECM when the 3rd Gen A/C turns on... Do i just put that Old A/C input from the 89 ECM to the LS1 A/C request input line and BOOM!!! i get A/C working right??
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Patience isn't your best quality, is it? 
If you have a pressure switch already, leave everything alone and run it as-is. Ignore that wire heading to the PCM, that's just there to signal the PCM to boost the idle a little bit when the A/C is running. Since you want a simple job, ignore the A/C trigger on the fans and let them come on with temperature like normal.
If you have a pressure switch already, leave everything alone and run it as-is. Ignore that wire heading to the PCM, that's just there to signal the PCM to boost the idle a little bit when the A/C is running. Since you want a simple job, ignore the A/C trigger on the fans and let them come on with temperature like normal.
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Verdad Gallardo I try to have patience but i want to figure this out so bad you know what mean?? LOL
Thanks so much brains, YOUR THE MAN!!!! I was looking at the 89 A/C wire diagram and it looks like when you turn on your A/C it triggers the Cooling Fan Relay. So i have to keep the old A/C Relay and the Cooling Fan Relay?? Or could i just use the LS1 Cooling Fan relays?
Thanks so much brains, YOUR THE MAN!!!! I was looking at the 89 A/C wire diagram and it looks like when you turn on your A/C it triggers the Cooling Fan Relay. So i have to keep the old A/C Relay and the Cooling Fan Relay?? Or could i just use the LS1 Cooling Fan relays?
Scraeder Valve... Question? When making up new A/C lines, wheres the best location to put the schraeder valve, or service port, on these two A/C lines? At the cannister/dryer on the larger line...on the smaller line...or should a service port be included in both lines? Thanks with the wiring info also. Comes in handy. Thanks
Last edited by LS1GMCTruck; Jun 13, 2009 at 04:53 PM.
i was going to use the LS1 set up but you make is sound like i could use the 89 set up as well?? Do i really need 2 fans or would one just do? The 89 set up is controlled by a cooling switch mounted to the passenger block. The LS1 doesn not have that huh? Just has the ECT that and thats what controlls the Fans right?
Truck guy: You need a high-side port somewhere between the compressor and the orifice tube, and you need a low-side port somewhere between the evaporator and condenser. Typically its mounted in/near the accumulator.
ram: You can use either, as long as they move enough air. One fan is typically enough for the LS1 unless you're in a hot climate and sit in traffic. You are correct, the LS1 is doing basically the same thing as your temp switch mounted in a cylinder head, it just does it with a temp sensor and PCM control of the relay.
ram: You can use either, as long as they move enough air. One fan is typically enough for the LS1 unless you're in a hot climate and sit in traffic. You are correct, the LS1 is doing basically the same thing as your temp switch mounted in a cylinder head, it just does it with a temp sensor and PCM control of the relay.
