964, 993 blower in an SC conundrum...

[Joe Bob]

Heater blower conundrum on my 911 SC with a 964 motor. 12 years ago, i pulled the relay and touched nothing else. Today with major help from my friend Brandon Steffenhauser I re-installed a blower, plugged in the relay on the rear fuse panel and tried to hook up the motor to the wiring harness.

The harness has no power, even with the levers pulled up in the cockpit. Fuses are good, the rear fuse gets power with the key on.....any suggestion on where to start trouble shooting?

Would like to get the switch to activate the blower when the levers are pulled up....

[pmax]

Make sure the relay's plugged into the right socket.

Try bypassing the relay.

[Joe Bob]

Jumper pins? Which ones? The fuse #5 has keyed power so that isn't the issue. Trying to get power to the harness where it should connect to the blower.

[pmax]

Pull the (black one) relay out.
Check pin 30 for power. Bypass 30 to pin 87 using a wire, the motor should run if it's ok. If not, trace the connectors from the blower, make sure it's plugged in. If it is, chances are the heater blower is toast.

The lever switch grounds pin 85 activating the relay.
Check the resistance of pin 85 to gnd to confirm a bad switch.

86 is power.
Check the middle fuse too.

[Joe Bob]

All three have power. 5 is switch 4 and 3 are 12v full time.

[pmax]

Originally Posted by Joe Bob

All three have power. 5 is switch 4 and 3 are 12v full time.

???

[Joe Bob]

There are three fuses in the engine bay....

[tshebib]

Did you test with the engine running?
My relay would only engage when it had the full 14.2 +/- volts from the alternator.
Just a thought.

[timmy2]

Pin 13 in the rear female 14 pin connector should be a yellow/black wire that gets power when the relay picks up.