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Well considering I'm not 18 anymore the heat/humidity really ruins driving the car for me and it's humid quite often throughout July/August so I want the A/C back.
What kicks the A/C clutch? Just 12v? Also does anyone have the wiring diagrams for the A/C circuit on an 84? I did some wire hacking when I did the LT1 swap so I have no idea what wires are for the clutch and pressure switches, etc.
Also I assume an LT1 style compressor clutch is engaged the same way (12v) but probably with a different style connector?
Basically I want my 84' to have A/C again but with an LT1 style compressor.
I did some wire hacking when I did the LT1 swap so I have no idea what wires are for the clutch and pressure switches, etc.
What did you trash, and what did you save when you did the swap? How about some pictures? Were the a/c refrigerant lines, condenser, and evap coils that are still in the car sealed at the time you did the swap? How long ago did you do the swap?
What did you trash, and what did you save when you did the swap? How about some pictures? Were the a/c refrigerant lines, condenser, and evap coils that are still in the car sealed at the time you did the swap? How long ago did you do the swap?
I plan on replacing all the components. Evaporator, condenser, drier, and getting used lines that will work with the LT1 style pump.
I just want to know the color wires I'm looking for as I cut most of the connectors off of the OEM crossfire engine harness. (In my defense most of the harness was hacked up when I got the car)
What signal is sent to the "Computer command control system" ? 12v once the HVAC controls are put in "Normal, Max, or Bi-Level? Is that the signal that tells the PCM to raise the idle and turn the fan on? (at least turn the fan on in an LT1 equipped car)
I'm assuming that's right as the whole system shown operates on 12v.
Last edited by v8vette84; Jun 22, 2017 at 12:45 AM.
What signal is sent to the "Computer command control system" ? 12v once the HVAC controls are put in "Normal, Max, or Bi-Level? Is that the signal that tells the PCM to raise the idle and turn the fan on? (at least turn the fan on in an LT1 equipped car)
I'm assuming that's right as the whole system shown operates on 12v.
To tell the ECM that A/C is on. Problably to increase idle air a bit.
Originally Posted by v8vette84
Also does anyone know why there is a diode in the wiring and what it's purpose is?
Protect against voltage spike when circuit opens. If you put a diode like that on the ignition coil primary you don't get any spark.
Since you have a seriously modified car, you certainly have a Factory Service/Shop Manual (FSM), don't you? The signal from the a/c Function Control Switch/Clutch control circuit to the CCC is shown on pg. 8A-25.
My '84 FSM is different than JoBy's. My FSM says the signal from the clutch wiring is from the junction of the High Pressure Cut-out Switch and the Compressor Clutch. JoBy's diagram above shows a different configuration, which must be wrong. The connection shown in his diagram would give a fast idle any time the a/c is selected, rather than only when the a/c clutch is engaged.
The radiator fan in the '84 is turned on whenever the a/c refrigerant pressure increases (a/c on) as shown in your FSM, pg. 8A-149. The Radiator fan is not controlled by the CCC. There is only one fan in the '84.
The diagrams I have are for 1984 Corvette, but it makes more sense to use the signal closer to the AC clutch.
I have confirmed the wiring in my '84, and the circuit (#59) to my ECM/CCC "A/C Clutch On signal" does originate at the junction between the High Pressure Cut-Out Switch and the Compressor Clutch.
If this signal originated at the Function Control switch (circuit #66), as JoBy's diagram shows, the idle speed would surge every time the a/c clutch de-activated.
Notice that JoBy's ECM/CCC diagram does show circuit #59 at pin 21. His diagram shows circuit #66 connects to #59. My FSM shows circuit #59 at both locations, with the note "Hot with A/C Clutch Engaged". JoBy's ECM/CCC pin 21 is labeled "A/C Clutch On Signal", which is correct!
I do not own a FSM. I have considered buying one but I was always able to figure out the issue without the FSM.
Anyway i could convince you to scan and post the page you are talking about in the FSM? So we can compare to the other diagram on here.
Also I do have an engine harness from a 96' LT1 Vette that I can probably use to get all the wiring I need. At least then I don't have to search for a diode and all those connectors and it will already be wired the way it should be.
I do have an engine harness from a 96' LT1 Vette that I can probably use to get all the wiring I need.
So this car isn't running yet? What ECM are you planning to use? What is your plan for the instrument cluster? Transmission? Did you buy the car with this engine swap, but incomplete?
So this car isn't running yet? What ECM are you planning to use? What is your plan for the instrument cluster? Transmission? Did you buy the car with this engine swap, but incomplete?
No, this car has been running for years. I'm using a stand alone LT1 harness. The stand alone harness has one green wire that goes to the PCM labeled A/C. That must be the wire that gets 12v when the A/C gets turned on and then the PCM raises the idle and turns the fan on. I'm using a 97' Z28 cluster and a T-56. ( I have a thread about the cluster).
I have been driving the car for years but finally I'm ready to get A/C working in the car again.
84' A/C Re-install help
