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240Z aftermarket A/C wiring question. HELP!


Zs-ondabrain

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I, of all people, have a wiring question for those of you who have a 240Z with A/C.

I'm rebuilding an engine harness and I'm going to ADD in the A/C controll wire. The questions are these.

1) what size is the blue control wire? 14 gauge or 16 gauge wire.

2) does the A/C pump only go on the left side of the engine compartment or is there a passenger side A/C pump? And if so, does it also only require a single activation wire?

I can't find any good pictures or threads that describe the wire, size and location and where it goes other than into the firewall into the passenger side. I've seen the thermostat switches IN a Z before but never followed the wires.

Any help would be greatly appreciated, not only by me, but my customers and all of you who, in the future, decide to have me rebuild your engine harness and add A/C into the harness.

Post here or write me directly at [email protected]

Thanks in advance,

Dave

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I have a 280 w/aftermarket AC. The blue wire on mine is 14ga. I have seen compressors mounted on either side of the engine compartment on the 240Z aftermarket systems. There are two terminals on the thermostat switch. One draws the power from the switch that turns on the heater fan. The other goes to the switch on the compressor clutch. I don't think it matters which terminal which wire is on since it just passes the signal through. Which side the wire goes through the firewall on depends on which side the compressor is mounted on.

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Regarding the location of the compressor it is my understanding that back in the day it would have been most common to have the compressor mounted on the right side on a bracket that obscures the fuel pump. Compressors mounted on the left side tend to replace the original air pump; I doubt that dealers would have removed that.

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I'm still waiting for the customer to figure out which Compressor he wants but I guess I could run a wire to both sides of the engine compartment.

But as long as it's just a contact or activation wire then it should be no big deal to run it to both sides. If it were a power wire, that actually carried amperage, then it would be a whole different story. Larger guage to the passenger side and kick it down a notch as it traveled to the drivers side.

Thanks alot guys, this has been helpful, now I just need him to make up his mind and I can finish this thing. I'll let him "chime in" when he makes up his mind or brags about the harness.

Thanks again,

Dave.

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My "factory" A/C was mounted on the driver side above the smog pump. (York compressor) It had a single hot wire to the clutch.

My dealer installed York system by FrigiKing is also installed on the driver side above the smog pump.

As a point of interest, the A/C compressor could be activated by the top heater control lever by being placed from "Vent" to "Off". This was accomplished by a micro switch being activated at the end of this cable under the passenger side when the vent door is closed. As long as the A/C

thermostat control rotary switch was out of the off position, the A/C could be turned on and off by sliding the top vent control to "OFF" or "Vent".

Since my car was restored, and this was never reconnected, I have been search for the dealer wiring diagram for this install so I can reconnect this micro switch correctly, again.

If anyone has this diagram or knowledge as to how to correctly hook up this micro switch, It would be a big help to me and may assist Dave with his install. Thanks.

Dan

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What Dan says is also true on my car. The compressor will only come on with the top lever in the Off or Vent position, with the fan lever on at any speed, and the rotary control out of the off position. I had to change out the control panel once but I didn't note how it was set up. I just plugged everything back in as it was before.

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actually Steve (Madkaw) that diagram is very useful. It shows a 10 amp fuse and that lets me know that the 14 gauge wire will be sufficiant for the activation wire I plan to run.

Thanks guys.

Dave.

So, Dave, I am really stupid when it comes to electrics and reading wire diagrams, but it appears that in madkaw's diagram the power source for the compressor is the heater control switch and the toggle switch shown in his diagram could very well be my micro switch which is opened and closed by my vent control slide lever. Does this sound correct to you?

I may be getting closer to my answers.

Dan

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Dave and all----

I'm the laggard that "Electrical Hero" Dave mentioned in the post above.

Thanks to all of you that contributed to his thread to help answer his question.

I have decided that running the wire to the driver's side would be best since it appears that the A/C compressor and clutch have been mounted there regardless of which style of compressor was used. (early piston York or later rotary Sandlin)

Does anyone have pictures which show the mounting of these types?

I have access to a complete York unit, but it is mounted to the passenger side. Will the bracket simply reverse for the driver's side?

I understand that the rotary type Sandlin compressors are more efficient and more reliable, and as such I am leaning toward using it.

Any thoughts and opinions from ya'll concerning the pros and cons of these installations are much appreciated!

Thanks again.

Jim D.

"Zup" :bunny:

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The Sanden SD508 is simply a better compressor than the upright York. The main problem with the 'York' system is the design. It pulls the cold air through the system rather than pushing it like most factory systems. Using a rotary type compressor will make that system cooler but it won't ever be as cool a a system with a center mounted evaporator. I don't think the bracket is reversible. I don't have a picture of the Sanden on the driver's side on a 240Z but here are the others.

York on driver's side:

63ubafp.jpg

York on passenger side:

6c3lutw.jpg

Sanden on passenger side:

62rit6s.jpg

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  • 3 years later...
  • 8 years later...

 71Z..where does the positive black wire on the AC compressor hook up to? a mechanic's did some work on my electrical system and left that wire lose. Does it hook up to the AC control thermostat box if it does but were? when I look in the back there's only one red wire hooked up going back  torn Center panel. the black wire from the compressor clutch is just hanging there  it's been cut. Does it need to be hooked up to the positive blower motor ?

Edited by tetert1
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19 hours ago, tetert1 said:

 71Z..where does the positive black wire on the AC compressor hook up to? a mechanic's did some work on my electrical system and left that wire lose.

Which side is hanging?  The compressor side or the harness side?  Does the car have factory AC and you just got a new compressor?  Or is the new AC system completely new?

You posted in somebody else's "aftermarket" AC thread so it's not clear what you're working with.

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It's a 71 Z with a factory AC it was working at one time. the guy was supposed to fix my gauges and lights and he took out a whole bunch of wires and put some gauges in on the bottom of the  glove box I left the car there and when I came back a few weeks later he did all the stuff I didn't even tell him to anyway I'm trying to get the AC hooked up again and running the clutch compressor positive wire comes through passenger side. And it was tied up by the thermostat control box where does it hook up to. I have seen a 72 and it goes in by the driver side and runs up to where the fuse boxes and it does have a fuse in the line..  tomorrow I'll try to take some pictures and show you what I mean on the 71 Z

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Use a meter or a test light and see if the wire gets power when you move the lever to AC.  There's only a single wire to the clutch, it ground through its mounting points, I think.

Find the wire that powrs up with the lever at AC and connect it to the wire at the compressor.  

Couldn't find a 71 diagram, but here is 76, showing the ground circuit.  Your 71 might not have the magnet valves.

image.png

 

Edited by Zed Head
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There is no lever to power on the AC you just turn on the fan switch and turn the thermostat control to the right and a tiny green light comes on and cold air starts coming out the vents so where does the black positive wire from the compressor hook up to? Maybe I need to hook it up 2 a positive wire to the blower fan motor with a toggle switch. When I hooked a positive wire from the battery to the loose black wire from the clutch the green light from the control thermostat box came on

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9 minutes ago, tetert1 said:

There is no lever to power on the AC you just turn on the fan switch and turn the thermostat control to the right and a tiny green light comes on and cold air starts coming out the vents so where does the black positive wire from the compressor hook up to? Maybe I need to hook it up 2 a positive wire to the blower fan motor with a toggle switch. When I hooked a positive wire from the battery to the loose black wire from the clutch the green light from the control thermostat box came on

The 71 guys would know for sure.  You're almost there by yourself though.  Just figure out how the green light could come on.  71 might have a ground circuit back through the green light.

Learn how the AC compressor clutch works.  It's just an electrical system.  You can do it.  Seriously, it will be good for you.  When you turn the thermostat control to the right you must be competing the circuit through the AC compressor.  Just ask yourself "how can this be?"

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A caution to be aware of... My car had the dealer A/C with the York compressor mounted on the drivers (left) side above the air pump. I had also installed a Champion 3 row aluminum radiator and the dual electric fans from MSA. The fans on the provided shroud won't fit with the old York mounted where it was. I bought this compressor upgrade kit for my 240Z that mounts where my deleted air pump was and it fits just fine along with having the Sanden compressor upgrade.

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From the AC compressor clutch I ran the positive wire with a toggle switch to a hot wire. Found some rubber O-rings from O'Reilly's  that were close to what was on it..Filled compressor with R134 freon.and it's  blowing cold air.

20200416_143609.jpg

20200416_122634.jpg

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