HVAC fan quit working - '94 coupe
06-08-2007, 02:51 PM
#1
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HVAC fan quit working - '94 coupe
It doesn't blow air on any speed setting. It's not the electronic unit.
I seem to remember it working once or twice after it quit, but I can't say for sure. It won't work at all now. The speed does vary a little, but it's more dependent on vehicle speed, not button setting.
Does the relay control the fan blower entirely? I wonder if it could be that or just a fuse? I was gone for a week on vacation, and just remembered today that it wasn't working, so I haven't had a chance to do any troubleshooting or look at the FSM yet.
Anybody got any suggestions before I get to digging?
I seem to remember it working once or twice after it quit, but I can't say for sure. It won't work at all now. The speed does vary a little, but it's more dependent on vehicle speed, not button setting.
Does the relay control the fan blower entirely? I wonder if it could be that or just a fuse? I was gone for a week on vacation, and just remembered today that it wasn't working, so I haven't had a chance to do any troubleshooting or look at the FSM yet.
Anybody got any suggestions before I get to digging?
Check for voltage at motor.
06-08-2007, 07:40 PM
#4
Le Mans Master
If I remember the '94 correctly, there are 2 relays - One is used for low and the other is more or less a direct connection for max. Most of these manual circuits flow through a Resistor Pod (mounted on the Evaporator Case) and then onto the Blower Relays. Start by jumpering the blower to the battery. If it works, I'd guess the resistor pod is shot. General troubleshooting for the Resistors begins by checking for battery voltage on the input side and then for something less (on all speeds but max) on the output or at the Relays. It would be unusual for both Relays to be shot and whatever fuse is protecting it usually only opens if there's a dead short in the motor.
06-08-2007, 10:07 PM
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Unplug the fan motor and jump 12v to the motor wires. This will tell you if the brushes are still making connection to the armature. Brushes don't last forever!
06-09-2007, 07:02 AM
#6
Safety Car
In my experiences with bad brushes, the symptoms can be intermittent.
That's because the armature can sometimes make contact with the bad brushes when you hit a bump or hit the motor with a fist.
In one case, I was 100 miles from home, started the car, and the A/C blower wouldn't work.
I figured the brushes were bad on the motor and got under the hood and hit the motor with my fist -- it started running immediately.
However, I also knew it would happen again -- so, I replaced the motor.
Tom Piper
That's because the armature can sometimes make contact with the bad brushes when you hit a bump or hit the motor with a fist.
In one case, I was 100 miles from home, started the car, and the A/C blower wouldn't work.
I figured the brushes were bad on the motor and got under the hood and hit the motor with my fist -- it started running immediately.
However, I also knew it would happen again -- so, I replaced the motor.
Tom Piper