944 AC Blower Fan Issues

[jwolfe]

Hey everyone, need help identifying a problem with my ‘86 NA 944

2 weeks ago my AC blower fan stopped working (all 4 speeds) I can still faintly feel cold air from my AC when driving at speed (so I know it’s the blower only)

My first thought was the blower relay, I swapped it with my horn relay as a test and sure enough that worked and ordered a new one. I didn’t drive the car for a couple weeks and went to install my new relay today and come to find it’s not working. I re-tested with the horn relay and that also wasn’t working now.

Are there any other fuses or relays that would effect this for some reason? Im hesitant to say its the resistor pack as if that fails, the blower typically still works at speed 4 and/or the defrost front vents button.


Update:
I took out my fan resistor pack and sprayed it with deoxit and soaked in vinegar. nothing changed
Ive hooked up the blower motor directly to a power source and it kicked on so that works ok.

Thanks!
Justin

[jwolfe]

Originally Posted by 944 Ecology

The best test is a voltage check at the connector for the blower motor itself.

Apply 12 vdc to one side and ground to the other side. If the motor works, then focus on the resistor pack.

Typically, a resistor pack failure only affects the 3 lower speeds and the highest speed works.

The connector you are referring to is from the blue wire correct? Whats a cheap power supply worth buying and using to test parts?

And I'm soaking the resistor in vinegar to make sure its not a contact issue. But as you said, it would theoretically still work on the highest setting, which it doesn't.

[9FF]

Originally Posted by jwolfe

...Whats a cheap power supply worth buying and using to test parts?...

Buy a long piece of 20 amp automotive wire and two insulated crocodile clips from your FLAPS, attach one end to positive terminal of battery = cheap power supply to test parts.

[jwolfe]

Originally Posted by 944 Ecology

According to the wiring diagram, the ground wire is brown and the 12 vdc wire is black with a red stripe.

sorry. I was referring to the outer casing of the wires, not the physical wire colors.

[jwolfe]

Originally Posted by 944 Ecology

Yes, the two expesed terminals at the black connector are the points to which to connect the ground and 12 vdc.

I tested and the blower motor kicked on with direct power to it. So I can rule that out...Now I wonder what could be going on. as you mentioned if the resistor pack is dead, the blower should still turn on at the 4th speed or on defrost/cycle. But mine wont kick on at all.

[9FF]

Originally Posted by jwolfe

I tested and the blower motor kicked on with direct power to it. So I can rule that out...Now I wonder what could be going on. as you mentioned if the resistor pack is dead, the blower should still turn on at the 4th speed or on defrost/cycle. But mine wont kick on at all.

It’s not a complicated circuit, fuse, relay, resistors, switch.

Like you said the resistors are bypassed if the switch is on full, so if it’s still not working on full then it’s not the resistors. You’ve tested the motor so that’s ok, that only leaves the fuse, switch and relay to test, you can bypass each one with a piece of wire. If that still doesn’t find the issue get your multimeter out and start checking your wiring.