AC Wiring Questions

[Kovmat]

I know this is not exactly the time of year to be thinking about AC but I am at the point that I am wiring up my Hybrid and a have a couple questions.

I am using an aftermarket AC system (Vintage Air) in my Hybrid project and need a little help.

I am looking at the schematic of the ECM harness and there are 2 wires coming from the ECM pos A2 (AC clutch control) Dk Green-yel wire and pos B8 (AC signal) Lt blue wire. Both of these wires go to the AC cutout relay.

Now I look at the AC schematic and I see that there is a pink-blk wire that goes from the AC cutout Relay to the Brake-sw. My schematic is a bit blurry, but that is what is looks like.

Here are my questions:

1) Assuming I am reading that correctly, what is the purpose of having that relay connected to the brake switch?

2) The compressor has 2 connectors going to it, I know the flat one is for the clutch. I am not sure what the round one if for. Is that the pressure safety switch?

3) The schematic for my Vintage Air unit only shows one wire going to the AC clutch. If I wire that directly to the compressor clutch what would be the downside of bypassing the ECM and AC cutout relay? Or should I just replace the Lt green wire going to the cutout relay and replace it with the wire from my Vinatage air unit and leave everything else in tact?

Thanks,
Matt

 

[mikestertwo]

Here are my questions:

1) Assuming I am reading that correctly, what is the purpose of having that relay connected to the brake switch?

2) The compressor has 2 connectors going to it, I know the flat one is for the clutch. I am not sure what the round one if for. Is that the pressure safety switch?

3) The schematic for my Vintage Air unit only shows one wire going to the AC clutch. If I wire that directly to the compressor clutch what would be the downside of bypassing the ECM and AC cutout relay? Or should I just replace the Lt green wire going to the cutout relay and replace it with the wire from my Vinatage air unit and leave everything else in tact?

Thanks,
Matt

1) The AC circuit gets it's power from the same power source as the brake switch which goes to the ECM/SOL fuse. The brake switch has nothing to do with the AC circuit.
2) The round connector is for the pressure cycling switch. It opens below 25psi to protect the compressor
3)If you wire the clutch directly the compressor it won't shut off during WOT operation or if the compressor is low on freon it won't shut off and you could burn it up. I would leave it wired to the computer. I don't know the wiring scheme on a Vinatage air unit so I can't tell you how to wire it in unless I had a schematic of it.

 

[Kovmat]

Thanks for the reply. Makes a lot more sense now. From the info over at GNTTYPE.Org the input to the ECM on the Lt Blue wire (B8) is 0 or +12Volts. Assuming that the output of the Vintage air unit is either 0 or +12V it should be OK. Would you agree with that?

Thanks,
Matt

 

[Kovmat]

Oops, spoke too soon. I am still a little confused. Maybe I am looking at the wrong schematic. It does not match what I have. Schematic

The round connector (press cycling switch) is wired after the gound side of the clutch. So power from the relay goes to the clutch then to the switch then to ground to complete the ckt.

What I am trying to find is the wire that goes to the ctl pannel to turn on the compressor. I think it is the Lt blue wire, it goes to this connector.



Can someone tell me what this connector plugs into?

Thanks,
Matt

 

[mikestertwo]

I think you are using the wrong schematic. The one you are using is for the electronic digital control used in some 86's. You should be using the schematic for the manual control AC used in the 86's and 87's.

 

[S10xGN]

I know this is not exactly the time of year to be thinking about AC but I am at the point that I am wiring up my Hybrid and a have a couple questions.

I am using an aftermarket AC system (Vintage Air) in my Hybrid project and need a little help.

I am looking at the schematic of the ECM harness and there are 2 wires coming from the ECM pos A2 (AC clutch control) Dk Green-yel wire and pos B8 (AC signal) Lt blue wire. Both of these wires go to the AC cutout relay.

Now I look at the AC schematic and I see that there is a pink-blk wire that goes from the AC cutout Relay to the Brake-sw. My schematic is a bit blurry, but that is what is looks like.

Here are my questions:

1) Assuming I am reading that correctly, what is the purpose of having that relay connected to the brake switch?

2) The compressor has 2 connectors going to it, I know the flat one is for the clutch. I am not sure what the round one if for. Is that the pressure safety switch?

3) The schematic for my Vintage Air unit only shows one wire going to the AC clutch. If I wire that directly to the compressor clutch what would be the downside of bypassing the ECM and AC cutout relay? Or should I just replace the Lt green wire going to the cutout relay and replace it with the wire from my Vinatage air unit and leave everything else in tact?

Thanks,
Matt

PM me with your e-mail and I'll send you a diagram of how I wired my S-10 swap A/C.