Hey guys! I'm hoping there may be a "wiring guru" that can help me out with this one. I'm in the process of retrofitting the A/C heater control panel into my Datsun 280Z. It was easy enough to get the fan switch wired in, but I'm hoping someone may know or have a wiring diagram to tell me which wire is for the A/C request button and which one is for the back lighting to illuminate at night, as those are the only 2 things that I need to get working with my setup. I got the pig tails from the '99 Max that it came out of, so any help is appreciated. Thanks guys!!

 

The wire to energize the a/c compressor is a light green/red stripe wire. It is in the smaller connector in the one corner. In the Maxima, this wire gets connected to ground in order to turn the compressor on. I hope the Z works the same way.

The illumination is 2 wires. This is because the light dims with the instrument panel. The 2 wires are pin 15, blue/yellow stripe and pin 16, red/yellow stripe. Pin 15, blue/yellow stripe has constant 12 volts from the light switch. Pin 16, red/yellow stripe is a ground from the dimmer switch that will have a varying voltage from 12 to zero. 12 volts means light off, zero volts means light on full brightness. I was looking at the service manual for a 1977 280Z and the Z green/white stripe wire comes from the light switch with 12 volts and the red/blue stripe wire comes from the dimmer switch.

 

Dennis,

I really appreciate the input. The illumination was easy enough, so that one is done.

As for the A/C "on" switch, besides the wire you mentioned going to ground, is there another that is a A/C power wire? Also, looking at this panel, I assume that the solid black does to ground? Are there wires that need either accessory or constant power?

Since the fan switch is essentially a "standalone" switch, that was easy. There is one wire that goes from the fan switch plug to the larger of the 2 other plugs. Is that one needed?

I also should mention that this is the manual control panel and not the digital one.

Once again, thanks a bunch!!

 

No. On both cars, the 12 volts for the a/c compressor clutch comes from a fuse, to a relay. When the ground signal from the control panel energizes the relay, contacts inside the relay close and the 12 volts is then sent to the compressor clutch.

That is correct. In the 99 Maxima, solid black wires (no color stripe) are only used for wires that are directly connected to ground. If the ground wire goes to a switch of some sort, then the wire coming out of the switch will not be solid black. It may be black with a color stripe or not black at all.

Yes, accessory power. This is a light green/black stripe wire in the big connector. But this not used for the a/c compressor. In the 99 Maxima, the control panel push buttons send 12 volts to small electric motors that move doors in the air ducts to direct air flow to the different air vents. I don't know for certain if the Z uses motors to direct air flow. I would have to read the manual.

Yes. I think you are referring to the orange/black stripe wire. The fan switch has 6 wires. When you look at the connector, the middle 4 are for the fan speeds. The solid black wire on the one end connects to chassis ground. The orange/black stripe wire on the other end is the ground that will eventually energize the a/c compressor relay. In the 99 Maxima, if the fan switch is turned off, the compressor does not run.

So the ground signal to energize the a/c compressor relay goes like this:
1 - chassis ground to the fan switch.
2 - to the a/c push button in the dash control panel. Comes out on the light green/red stripe wire.
3 - to the a/c refrigerant pressure sensing switch under the hood.
4 - to the ECM computer. This step does not apply to the Z.
5 - to the a/c relay.

 

Dennis,

Thanks again. I am getting it figured out. Of course, I had to make things just a little more complicated than just "using the Maxima panel in a 280Z" as I have a Chevy LS6 in the car and have to also make it play with the PCM which controls the A/C compressor, fans, etc. Not sure if the A/C request button on the panel will work with the setup I have without some tricky wiring. From what I have read, the A/C request runs off a 5 volt reference, so......

 

Is the PCM a Chevy module? I would think that the GM a/c compressor clutch runs on 12 volts like the Nissan one. If you can keep using the Nissan a/c compressor relay, then all you would have to do is bypass the PCM and run a wire to the a/c compressor from the relay.

This is essentially the way Nissan does it.To "convert" the Nissan ground signal to a 5 volt signal isn't really that hard, but you will have to buy/make a 5 volt converter. Or get it from the PCM?

 

You are correct in that the GM compressor does get a 12 volt signal to it. I don't have any of the original Datsun A/C parts in the car, so I've added everything and have the A/C relay as part of the BP Automotive DIY Premium Harness kit to make the LS motor a standalone setup. It looks like I just need to attach the ground wire (light green/red) in the Maxima control panel to the A/C request wire in the GM harness, which is the C230-F pin that is c2 pin 17 circuit 762. (if I'm getting this right) ;^) Almost there, once I get this done! Thanks again!!

 

Don't forget that the light green/red stripe wire from the Maxima control panel will have a ground on it when you turn the a/c on. Just make sure this is what the GM wiring wants.

 

Well, I guess it wouldn't be quite that simple, as the GM setup requires a 12v power to turn it on, not ground. Looks like I'll be adding in a relay between the panel and A/C request wire to send power to the PCM. Good thing a little searching on the internet can make it a little easier to get it figured out. Do you see this as the answer or do you have another suggestion?

 

Use the relay as shown in the upper right corner of the diagram. I don't know of anything that would be simpler than this.

The relay does not have to be a very big one because there isn't going to be very much current going through it, probably less than one amp. If you can find a low power relay, it will be a smaller relay than the relays you see in automotive use. But the relays used in the cars aren't really that big, so the extra effort may not be worth it.

 

I picked up a 12v micro relay from the local electronics store (since Radio Shack is no more), so I'll wire it that way. Since I am only using the A/C on switch and fan speed switch to run those via a ground signal, do I need to run power to that other wire to get the A/C light to illuminate on when it's in the "ON" position? I'm assuming so or will it light up once it grounds the circuit?

 

I think you will. I don't have any Nissan documentation that shows or talks about the lights in the buttons. But all the switches themselves are dealing with grounding something, so the light bulb power isn't coming from within the switch.

Even the fan switch does not get 12 volts to it. The one side of the blower motor is connected to 12 volts all the time and the fan switch grounds it to make it spin.

Speaking of the blower motor, are you aware of or do you have the special resistor that gives you the fan speeds? Without it, only the high speed, position 4, will make the blower motor run.