Here's a thread where we are having problems with a blower fan on a A/C equipped 1975 f250. I have no diagrams on this system, and his wiring needs some help. Can anyone familiar with this system help? Does anyone have a diagram they can email him? Any help is appreciated. Here's the thread.

https://www.ford-trucks.com/forums/6...t-working.html

 

In posted my offerings

 

Bump - Thanks to all that have helped out - I must be pretty close to getting this figured out thanks to Mil1ion - he has gone above and beyond.

If anyone has pictures of the AC relay and the wires that go into it that would be most helpful. If you can please follow the thread posted above...Thanks!

 

Did you mean the relay mounted to under the dash

http://i69.photobucket.com/albums/i7...fo/acrelay.jpg


or that other one that doesn't exist on the F-series ?

 

:0 That's exactly what I needed to see. See my plastic harness was partially melted and wires were pulled out, so I couldn't tell what color wires went where. Now I see. I'm pretty sure I have already tried that combo of wires on prongs, so it whould have worked for me, but it didn't - the fan still will not shut off or turn on with the relay wired in.

Why do you have that other red/black wire not connected to anything? It should hook up to the blower resistor in the plenum.

 

I haven't done much to the truck since I got it last year.

I'll check it out in detail someday.
Right now I am looking for the lost keys for it

 

Mike I'm really surprised this schematic I posted didn't help you.