Vintage Air AC in a Gen2 Type 65 Coupe with Gen2 Coyote.

[Gbeck]

Cross posted from my build thread. I figured that it's pertinent to this forum.

I have the Vintage Air AC system that Factory Five sold for the Gen 2 Coupe and I'm trying to mate it to a Coyote from a 2015 Mustang. Fortunately the engine came with the AC compressor and the suction and pressure hoses that attach to it. And I harvested the compressor clutch connector from the original engine harness. That's about a thousand buck in parts!
The plumbing is pretty straight forward but control of the fan is a mystery to me at the moment. I wired the radiator fan so as to be controlled by Coyote Control Pack. But it has no provision for air conditioning. There's the Vintage Air trinary switch. Then there's the pressure switch in the hose from the compressor to the condenser (with no mating connector, pigtail or pin out). Do I use the trinary switch, the pressure switch, or both? Do I wire the AC stuff to provide an alternate power source to the fan? Or do I wire it to provide an alternate ground to the Control Pack fan relay?
I guess I'll figure something out sooner or later. But if anybody's been down this road I'd appreciate some insight!

[edwardb]

I can't provide a complete answer because I have the Factory Five A/C-Heater setup in my Gen 3 Coupe. But FWIW, I too have a Coyote with the control pack powering the cooling fan. The Factory Five instructions showed powering the cooling fan from the RF panel and routing the RF green thermo switch wire (relay ground) to the trinary switch. That would cause the fan to be powered from either source depending on whether triggered by the Coyote system or the trinary switch. I'm generally OK with electrical and wiring, but questioned this setup. Had a conversation with Factory Five, and they assured me it was OK to wire that way. It's done and working just fine. The Coyote runs cool enough that the control pack rarely turns on the fan. (The Gen 3 Coyote has a much more "reasonable" temperature setup from Ford than the Gen 2. Separate subject.) But with the A/C running, the trinary switch does switch the compressor and cooling fan on and off like it's supposed to. Just took a drive yesterday with outside temps over 90 and it's working the way it's supposed to.

My setup doesn't have any kind of pressure switch in the hose. So no help there. I'm a newbie at this A/C stuff. This was my first ever installation. These instructions from Factory Five obviously aren't for your setup. But the last page has a schematic that may be of some use. Good luck. https://www.factoryfive.com/wp-content/uploads/2019/01/AC-HEATER-DEFROSTER-COUPE-Gen-3.pdf.

[Gbeck]

That’s a huge help, Paul! I didn’t know that this doc existed. The last page is just what I need and I’m be sure that there’s some good guidance in the rest of it.

[Gbeck]

After studying my wiring harness, wiring diagrams, and input from a few folks I now have a plan for the AC plumbing and wiring.

Plumbing:
I'll use the compressor hoses that came with the Coyote engine from the Mustang. I'll cut the end of the suction hose and crimp on a #10 splice with a service port for the low side. Likewise I'll cut the end of the pressure hose (eliminating the Mustang service port and pressure switch) and crimp on a #8 splice with a service port for the high side and extend the hose to the condenser. The rest of the system will be pretty conventional. I got some nice 90 degree bulkhead connectors that I'll use to run the hoses through the firewall and fabricate a mounting plate to take the strain off the aluminum.

Wiring:
I will leave the Coyote Control Pack fan wiring in place to power the fan based on engine temperature. I'll use the wiring, fuse and relay in the Ron Francis harness to power the fan based on AC demands via the AC thermostat switch and the trinary switch from the Vintage Air kit. I'll splice a connector into the fan power wire to attach the fan power wire from the Ron Francis harness.
I looked into the consequences of current back feeding from one fan power circuit to the other. Both circuits use a relay that will effectively block current coming from the other circuit. So back feeding current won't be a problem.
And all of the wires I need are available in the harness at the front of the engine, Yay!

[Alan_C]

Vintage Air has wiring instructions for their trinary switch. I plan to follow this approach with my 2nd Gen Coyote using the OEM accessory drive and compressor.

https://www.vintageair.com/instructions_pdf/11086-VUS.pdf