a/c fan wont work!

[elmauro86]

ok my 88 gm a/c fan wont blow air out of the vents, but the compressor does engage, and cool air slowly comes out of the vents so the compressor works, what parts of it should i check with a dmm (like the speed switch on the a/c controls) and what should i check for? volts?? ohms?

help i'm gettin cooked every time i have to ride this car, it annoys me :guns:

[trwp72]

Fan motor

Three things will prevent it from coming on...

Fan switch... which will usually work in one speed but not others....

Fan relay, out near where the fan is bolted into the A/C box...
Tap on the relay with a small hammer and see if it engages

Fan motor itself...
Tap on the side of the fan motor with a small hammer and see if it comes on... sometimes you will get a "dead spot" on the windings where the brushes contact it.. you tap on it with a hammer and it starts working... (I have done that on NUMEROUS starters!!) but it WILL stop running again.. so go get a new one if this is what it is!


I have had to change out fan motors and fan relays.. but no switches so far.... so I doubt it is the switch... they seem to last... Relays and motors are junk tho... go to Advance, or somewhere like that. and get a lifetime warranty one.. I have replaced two on my 91 so far... only had to pay for the first one!!!

[elmauro86]

can i put +12v on the fan to test it? and which wire is + and which is - ?

[88grandmarq]

with the key on and the fan swith on, check for power to the reistor, then to the fan motor.
you can test the fan motor by using a 12V power source. polarity shouldnt matter, as the motor will turn either way when power is applied.

[elmauro86]

i cant seem to find a relay near the fan motor, wouldn't anybody have a pic so i can see it a little easier?

EDIT: ive run +12v to the thick orange wire, and everything works as it should, mabybe i need to trace it to wherever it ends?? (still cant find no relay anywhere, that might be the cause too right?)

[marquisman]

if the fan doesent come on at all, even on hi-mode, then chances are its the fan, if the fan comes on at hi-mode, its the resistor.

[elmauro86]

ok, i think i'm gonna take it to the a/c guys when i get some cash, for now i ghetto rigged a relay from the battery to the fan that makes it come on only when the key is in the on position :drug: will do for now as the heat is like 42º C and DAMN it gets hot inside the gm

@marquisman, the fan switch works with my rig, so my bet is the resistor is still good