fan wont come on when a/c is on

[auag]

on my 81 caddy diesel i'm trying to get the a/c working...but the radiator fan doesnt come on when i turn the a/c on....anyone have any ideas?

[TylerDurden]

I'd look at the relays in the path from the dash switch... In some setups the relays are on the shroud and vulnerable to atmosphere and battery vapors, and can corrode inside. Relays under the dash can corrode if a windshield leak drips on the fusebox.

[Fatmobile]

I think the plug for the switch is under the radio (on top of the controls).
See if it is still plugged in.
Check voltages there.

[air-cooled or diesel]

theres several relays that i think are for fan, 1 that is related to a/c is on top of rad, right near a/c high side sensors, check all sensors and connections, spray/clean w/electronic cleaner, there may be a sensor on head water flange, big sensor, also check radiator fan sensor at bottom drivers side radiator. another rad fan relay may be on relay board, by fuse box. check/clean fan contacts too.

[air-cooled or diesel]

i'm trying to get the a/c working...but the radiator fan doesnt come on when i turn the a/c on

so my first q? to this is, does a/c compressor by any chance turn on when you switch it on inside, and you say rad fan wont come on, so a/c is supposed to be disabled, safe mode,, does it have a charge in it?
dont forget to check fan and a/c fuses

[auag]

hey guys..thanks for the reply...i finally figured it out....in case someone else runs into this problem in the future...it was an inline diode that was blown...it was in the wiring harness behind the glove box