[MDPotter]

Originally Posted by derotoreut

So that wiring diagram that I posted is all part of Clinebarger's thread. I didn't understand that wiring diagram. It looks like there is a relay with pin 87 feeding into the fan relay. Could this be a way around from having to use a resistor and diode?

Can you show me how you installed your diode and resistor? Do you have any pictures? I will have to cut into my wiring to install this. I have no room to install them in my cab without doing some work. Can they be installed outside of the cab any way? This is all new to me.

Also can you confirm that the green wire in your posted wiring diagram is the blue wire in Vintage Air's Gen IV connection instruction?

That diagram from Clinebarger has everything wired correctly, but it doesn't incorporate the PCM fan trigger wires. The way it's wired doesn't take away the need for the resistor and diode.

Here is a picture of the backside of my fuse/relay block. The relay with two blacks and two reds is my fuel pump, ignore that. You'll see that instead of stripping a small section of insulation from the PCM blue wire going to 86 and tying onto it with the trinary switch blue wire, I put both wires on the same connector that the relay plugs into - just a little cleaner that way. I don't see a reason why you would have to put the resistor and diode right next to the fuse block, they just need to be between the relay and the trinary switch. You'll also see that instead of running two separate pink ignition wires to pin 85, I put two wires on one of the relay connectors and then jumpered over to the other relay. As far as how to install the resistor and diode, I soldered the lead of the resistor and the diode together, then wire to the other side of the resistor and the other side of the diode. Don't overthink it. Just make sure the resistor and diode are in the right order and that the diode is pointing the correct way. Once you have it all connected, you can test by touching the blue wire that leads to the trinary switch to a ground source (with the key on) and fan #2 should come on. Once you start it, you shouldn't have any check engine lights either which means the resistor and diode are doing what they're supposed to do.

The green wire in my diagram (running to pin 86 on fan #1) is the green trigger wire from the PCM. Are you looking at the green/black wire coming out of the trinary switch? The green/black that run to the compressor and A/C switch have nothing to do with the relays, they are part of the Vintage Air system only.