to anyone running a truck ac bracket

[ls1nova71]

That schematic is not for a truck. It looks more like an F body. I would do as Cline suggested and bypass the PCM control all together, or wire it like a truck. Having it controlled by the PCM doesn't really get you much. Have the fans come on with the trinary switch and leave the computer out of it, it will be easier in the long run.
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[cjohnson6772]

Great info guys. I had no idea that there was such a difference between cars and trucks as far as a/c working. I'm beginning to really regret my harness purchase. The schematic I have came with my harness. But I told him explicitly it was for a DBC Truck and 4L80e. I get back a harness for 60e. Easy fix but nonetheless......OK off my rant. I dug around through all the pin outs I could find and LT1swap.com after Cline's post and found the truck schematic which just shows the switch inline like he said. I've emailed my tuner to see about the segment swap. I know we flashed two different OS's but I'm almost certain we went back to truck OS. And enabled the second fan just by changing the pin from the a/c recirc door to fan 2. I will wait for a response back and in the meantime roll under the truck to see if my harness connector is 2 or 3 pin. Hopefully I can just jumper that connector and be done with it. Otherwise I will bypass the PCM altogether. Thanks as always. You two are gentlemen and learned scholars.
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[Hart_Rod]

Updates?
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[cjohnson6772]

Originally Posted by Hart_Rod

Updates?
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Apologies for the delay. I was able to get everything working through the PCM without having a retune and with minimal modification. Essentially the problem was my compressor and tune were for a truck and my harness was for a car. The car is a more complicated system by nature. I can say with no hesitation, there is no need for a trinary switch in this setup. A binary switch will work fine.

I've attached the part of the manual I got with my harness (I really should have bought a stock one and modified it after all was said and done). Pages 62-67 show the connector pinouts as wired. The first pic is of the provided HVAC schematic. Essentially an Fbody set up. I confirmed by crawling under the truck that the connector for the HVAC pressure sensor is in fact 3 pin (consistent with Fbody). I originally had spliced the wire from the clutch relay to the compressor and installed the Hi/Lo compressor side of the trinary switch in line. I spliced into the wire from C2-33 to pin 85 on the secondary fan relay and installed the Hi fan side of the trinary switch back to ground.

After some research (and help on this thread) I to removed all the splices I had installed with the trinary. Added the Hi/Lo compressor side of the switch from ground to C2-55 and left C2-11 empty. C2-11 originally controlled the recirc command. I think when C2-11 was grounded it would have originally activated C2-33 which used to be the recirc door control, but is now my secondary electric fan. I only used the one side of the trinary switch as shown in the diagrams. This is why you can get by with a binary switch.

Now, if I had it to do over again and my system was evacuated: install a binary switch in the low side of the system where I show my trinary switch is installed. Then wire another binary in line with the compressor clutch on the high side of the system. The only reason this would be better than the way I am currently wired is that it would allow the compressor to cut on and off based on low pressure as well and would not freeze over the evaporator core if the system is too large for the truck.

This post is a mess, but is cut and paste from some of my notes earlier in the process. Feel free to ask any clarifying questions. I have a pretty good handle on this now.

[cjohnson6772]

Also: To avoid running a wire all the way through my harness I simply moved the red/black wire from the 3 pin connector at the PCM end. I clipped it at the harness end and wiring to my trinary.

[Ford Assassin]

If using the stock AC evap box and/or condensor I can't imagine the LS compressor working very well since its a varable type compressor.

[clinebarger]

Originally Posted by Ford Assassin

If using the stock AC evap box and/or condensor I can't imagine the LS compressor working very well since its a varable type compressor.

The Delco V7 is a variable displacement compressor, These are only used on passenger cars.

The Delco HU6 & Denso 10S20F used in trucks & SUV's are fixed displacement.

[bigoilman]

Originally Posted by clinebarger

Without a mechanical fan it's Mandatory in my opinion! At low speeds/stopped you will need airflow across the condenser if Head Pressure gets to high (<250 psi)....High Head pressure will.....Decrease A/C performance, Blow lines, Break belts, Break the compressor, Break the tensioner & Smoke compressor clutches.




Do Not wire the Trinary to the PCM controlled relays, It will set codes & the PCM will freak out & turn the fans on at all times....Here's a diagram on the Correct way to wire it....

Wiring my VA last night and had a question about this post. My harness has the factory plug with one green and one black wire going to the compressor. Do I disconnect that plug, splice into the green wire and ground the black wire?

Thanks.

[clinebarger]

Originally Posted by bigoilman

Wiring my VA last night and had a question about this post. My harness has the factory plug with one green and one black wire going to the compressor. Do I disconnect that plug, splice into the green wire and ground the black wire?

Thanks.

The Black wire should already be grounded. Yes, the Green wire can be cut....Then run the Vintage Air Comp. Clutch wire to it from the Binary/Trinary.

[bigoilman]

Great. Thanks. There's so much misinformation out there about running VA in these swaps.

[Clyde65]

Cline hooked my AC up ( I have Old Air) and it has worked perfectly since. fans come on when they are supposed to. very pleased.

[Ford Assassin]

Originally Posted by clinebarger

The Delco V7 is a variable displacement compressor, These are only used on passenger cars.

The Delco HU6 & Denso 10S20F used in trucks & SUV's are fixed displacement.

Good to know since going to use a 10S20F with my crew cab dually swap.

I have my tune setup in HP Tuners so the fans are on automatically on whenever the ac clutch is engaged, but also will turn the fans off when reaching a set speed, in my case I set to 45 mph. I figure that should be enough airflow across the radiator, condenser, and intercooler (in my case).