VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 1939 heater motor

How can I test my heater motor, to see if it is functioning properly? There is heat coming out of the heater, but I don't feel any air being blown off of the heater.

Can I remove the motor without removing the entire heater unit?

How does the defroster work? Does it function all the time?

Under my dash, I have two switches both are white / amber, under the throttle and choke knobs, one rotates clock wise and lights up, I am assuming this one is supposed to operate the heater fan. From what I can see there is one wire going from the lighted switch to the fan.

The other is right next to the first and I have no idea what it does.

The heater box is brown wrinkle paint with two doors and has a round plate saying "Chevrolet Deluxe".

Thanks;

David

David,

Make sure the heater motor has power to it. There may be a fuse blown. You should be able to hear the motor run by the air being driven by the fan.

I think you will have to take the heater out to get the motor out of it. New heater motors come up often on eBay. I think they fit many production years.

I don't believe the rotating switch is correct for you car. I could be wrong about that. I don't like them because I almost burned up a car once owing to a short caused by the clamp on the back of it getting into other wires. It wasn't solely the switches fault but still...

Good luck with it.

Gene has a 39 (as well as others) and I'm sure he is a better source for information than I. From all the talk about winterizing the cars up north, he may be in hibernation status right now and only crawls out during periods that the sun is shining brightly. He should respond soon, though.

Charlie

If you turn on the ignition and then the fans, you should hear it running and feel air coming from the front of the heater. At the very least, if it's wired through the ignition, there should be a significant change in the current draw at the ammeter. The rheostat switch, the one that rotates, is for the heater and the other is for the defrost. I had to remove both motors and work with them to get them running again. If your fan is like mine, the defrost will consist of a motor on top of the heater with hoses that run up to the window. The heater motor is in the back of the heater and you need to remove the heater to get to it.

Brian

Both motors on my '41 heater were stuck. I removed the heater. Then, I removed both motors. Both could be turned slightly by hand. The bushings were very dry. They hadn't been run during the six years spent in inland Florida.

I didn't want to take 'em apart. I drilled a small hole just off center in the blind end of each motor so I could get oil on the rear bushings. I used 50-50 ATF and Acetone. I wet 'em (both ends) several times for about a week, attempting to turn 'em each time I oiled 'em. Both finally turned freely. They are now back on the car and running fine. Perhaps yours could be the same.

I can only find one wire going to the heater motor. When I look online I see two.

Should mine have two?

When I have the ignition on and rotate the one switch the knob lights up, I feel no air movement.

As for the defroster, does the heater need to be on before it lights up and blows?

If it's like the heater/defroster on my '38 the defroster works independently from the heater. Each motor has one wire and grounds through the case. If the motor is running you'll be able to hear it and feel the air. Bypass your switch to connect a jumper to the heater motor. If it's good it'll run then. If it runs with the jumper wire you have a bad switch.

'Suggest you reach behind the heater and see if you can turn the fan. It may be stuck like mine was (both motors were stuck) If it turns freely make sure you're getting power to the motor. You likely can't get to the defroster fan to turn it.

My switches were working but both motors were stuck - dry bushings. It took a bit of trouble and some patience but I avoided buying new motors.

Luck to you - - -

You can also use a multimeter to see if you have power going to the heater motor.