72 Fury blower motor... Which wires?

MBar · Sep 1, 2023

My car had factory air conditioning. My buddy and I put a new style compressor on it and he got the AC working! Unfortunately, previous owner did something under the dash and I had not noticed previously but there seems to be some sort of replacement switch for the fan on the dash. No matter what I do the fan stays on low setting. It's very tantalizing but certainly not enough air. This weekend I'm going to try to fix that and find the wires for the fan speed. Does anybody know what they look like perhaps color? Or where they go? On a quick examination I actually didn't see any wires going to the fan box looking under the dash. Has always any help is much appreciated

Big_John · Sep 1, 2023

The best thing you could do is download a Factory Service Manual here: Service Manuals – MyMopar

Once you do that, print out the electrical schematics for your car, get out some colored highlighters and trace the wires you need to look at. The FSM will have all the colors etc.

If you look at the wire labels in the FSM, you'll see something like "L7-18BK" . L7 is the circuit number. 18 is the wire gauge and BK is black.

MBar · Sep 30, 2023

Hey Fellas... finally got to playing with the car. I found the Blower motor resistor connection (under the dash or easier if the ashtray is out of the way).
I did get the chassis manual and studied section 8 Wiring diagrams. I am confused.
My goal to to get the fan working on high and medium because low is well, too low. Right now, If I press-in the A/C to turn it on, I get low fan and no way to adjust it. I want to put in some aftermarket switch as my dash switch is bad.
Anyhow, I want to figure out how to connect it. what leads should contact for each of the speeds? I know brown is low, light green is medium and dark green is high.
I used my test light to check for what is "hot" with key on and a/c on and off. Please see below for my results. Hot means test-light to ground and "Hot between" means test-light between two points.

The PO did a number on my under-dash wiring and I'm hoping the mess I see is only from the radio swap but I also had what looks like an extra hole cutout on my temp panel and a small switch installed. I now have that hanging under the dash so I can have my dash together while I figure this out. It's connected to two light blue wires and I can't tell where they go but the switch does not seem to affect anything. sliding my temp control does nothing (cable bad)

I don't want to just start jumpering things together as I see in the wiring diagrams there are resistors involved and I don't want to blow anything (other than sweet cool air lol).

Sooooo, what do I do to get select-able air flow? I don't want to try to pulll or replace stock dash components as it looks like a pain just to get the controls out. My heater control cable is shot but I am likely to just rig some alternate way for that. Love my car but I am ok with a bit of McGiver-ing. As always, appreciate any and all help