Where do the AC Drier/Receiver wires connect to? Need help tracing a wire

[groovezog]

It's summer here in the USA and I've been working on getting the air conditioning working in my 1991 Skyline GT-R. My car had a bunch of wiring stripped when I got it as a shell, but I've managed to get just about everything back together, and I've fixed all the climate control codes. It's no longer throwing any codes. 

The last thing (hopefully) that I can't figure out is where the wires lead from the AC drier/receiver pressure switch. I believe the two wires are green and light green, but I can't find those on my car's harness anywhere. 

My question is: Where do these two wires terminate exactly? 

If someone could trace them to a fuse box, relay box, or where they connect to a sub-harness, that would be extremely helpful. Also, could anyone confirm that they are always two green wires, and were never other colors?

Thanks for any help that can be offered. 
 

[Duncan]

Sorry they are physically long gone in my car, but using the excellent wiring scans GTSBoy did it looks like one side connects to the AC relay + trigger, and the other side to ECU pin 9 (AC relay). It connects for the AC pressure switch

well done if you've got this far without referring to the wiring diagrams or service manual

[groovezog]

On 7/12/2022 at 2:18 PM, Duncan said:

Sorry they are physically long gone in my car, but using the excellent wiring scans GTSBoy did it looks like one side connects to the AC relay + trigger, and the other side to ECU pin 9 (AC relay). It connects for the AC pressure switch

well done if you've got this far without referring to the wiring diagrams or service manual

Thanks for that. I'll try to unravel the loom coming from the AC relay (under the bonnet, right?) and see if can find a cut wire. It would still help if someone had a photo or something though. 

I've studied some wiring diagrams, like the one attached, but it doesn't show wire colors or how they route in the engine bay.  

[Robzilla32]

Once I cleaned away the grime, mine look like dark green / yellow stripe and light green. Looking at your pic again, I would say yours are the same.

[groovezog]

On 7/13/2022 at 3:11 AM, Robzilla32 said:

Once I cleaned away the grime, mine look like dark green / yellow stripe and light green. Looking at your pic again, I would say yours are the same.

Hey thanks for checking. Could you snap a photo of where your wires go? Even a general idea might help.

This isn't actually a photo of my car. I'm trying to find the wires and a general idea of where they lead.

[Robzilla32]

Sure. I will take some pics when I get to the car next. I took the one below last night.

As a general description, the wires pass throught a service hole underneath the headlight where they are then taped to another part of the loom. That is then routed behind the coolant overflow bottle and appears to lead up to the fusebox behind the battery.

Please consider that a. I am an amateur so, take what I observe with a grain of salt; and b. the wiring in my car like a lot from that vintage has probably been hacked around a bit.

[Duncan]

Well, the AC relay is in that fusebox near the battery. If both wires go there the ECU wire must continue in the loom in the guard and into the cabin through the main loom grommet.

[joshuaho96]

On 7/12/2022 at 8:59 PM, groovezog said:

Thanks for that. I'll try to unravel the loom coming from the AC relay (under the bonnet, right?) and see if can find a cut wire. It would still help if someone had a photo or something though. 

I've studied some wiring diagrams, like the one attached, but it doesn't show wire colors or how they route in the engine bay.  

This is for the R33 GTR but I can't imagine the routing is going to be dramatically different as the placement of the critical components seems to be mostly the same. 36 is the AC pressure switch. Goes towards the driver side near the headlight and then up towards the relay/fuse box which has the AC relay. From there it goes into a grommet in the firewall into the driver side which then goes into the spaghetti inside the dashboard until it gets into the back of the AC unit. It also is connected to the ECU harness somehow too, probably to help with AC idle-up.

Edit: Interior body harness looks like this:

Edited July 14, 2022 by joshuaho96

[groovezog]

On 7/13/2022 at 10:44 PM, Robzilla32 said:

Sure. I will take some pics when I get to the car next. I took the one below last night.

As a general description, the wires pass throught a service hole underneath the headlight where they are then taped to another part of the loom. That is then routed behind the coolant overflow bottle and appears to lead up to the fusebox behind the battery.

Please consider that a. I am an amateur so, take what I observe with a grain of salt; and b. the wiring in my car like a lot from that vintage has probably been hacked around a bit.

Hey, thanks a ton for this. I think that's going to be pretty helpful. I'll dig into my engine bay and maybe unravel this wire loom to see if I can trace it back to the fuse box or something. Thanks again. 

 

On 7/14/2022 at 1:27 AM, joshuaho96 said:

This is for the R33 GTR but I can't imagine the routing is going to be dramatically different as the placement of the critical components seems to be mostly the same. 36 is the AC pressure switch. Goes towards the driver side near the headlight and then up towards the relay/fuse box which has the AC relay. From there it goes into a grommet in the firewall into the driver side which then goes into the spaghetti inside the dashboard until it gets into the back of the AC unit. It also is connected to the ECU harness somehow too, probably to help with AC idle-up.

Edit: Interior body harness looks like this:

Oh, this is pretty helpful. I had found these on the site, but they were all sized-down and pixellated so I couldn't read anything. Thanks for these high-resolution images.