The Stovebolt Site Forums The Shop Area The Electrical Bay Heater fan motor question

Hey all. I looked through the electrical posts but couldn’t find info on Harrison heater (non-fresh air) fan motor numbers. It’s the smaller round one. I’m converting to 12 volts and wanted to know if P.O. switched the fan motor to 12 volts ( he did switch the generator, voltage regulator, and headlights to 12 volts). I saw no resistor in the line to the heater. I took the heater apart, removed the motor from the round core, and saw the numbers 5047678. Also Delco Appliances. Anyone now if this is a 6 volt motor or a 12 volt motor? If it;s a 6v, what do you recommend for conversion; resistor on 6 v motor or switch to 12 v motor. Thanks
Slowly but surely.

I’ll jump in here with opinions, right or wrong. One of the really good Chevy truck guys might run your numbers and put you on the correct answer.
If you can find and fit a 12 volt motor that would be the best option. A six volt motor with resistor is a band aid used when nothing 12 volt can be found and installed.
If no information is forthcoming, then bench testing would be a way to find out. You will need a 6/12 volt source. I have a heavy duty dc power supply for this. A 0-20 amp dc ampmeter and jumpers. I would load the motor by attaching the fan blade. Check you schematic to see what the fuse size is. Hook it up and see how much current is draws. Also a strobac would be helpful to measure the motor rpm. If the current and rpm are within reason at 12 volts, then run it.

** Delco #5047678 Googles to be a 12 volt dc motor. **

Perhaps you already have your problem solved as Marzach said. You already have a 12v. But if it doesn’t fit or you need a cross reference...

I switched mine out to a 12 volt and it was super easy. I just had to trim the shaft a tiny bit to get it to sink down in the heater housing enough to clear. However, I did not have a round core heater. Here is the discussion I used:

https://www.stovebolt.com/ubbthread...motor-replacements-napa.html#Post1136055

Scroll to the bottom and read Grigg’s post. One of those two NAPA numbers could be your new friend. I used one of those. I can’t remember exactly which one, but Napa ordered both in for me and I brought in the old 6v, matched it up and I was good to go.

Thanks Marzach, I’ll test it and reinstall if good. My quest for 12 volt conversion may be easier than I thought due to the P.O. already putting in most of the 12 volt stuff. How do I know if the sending unit is 12 volt ( the last of the 12 volt conversions or is there any more that needs to be done?). Thanks to the rest of you guys too. What an invaluable resource Stovebolt nation is!

So I tested the motor and it works! No smoke or heat. Original cloth wire brittle and bare so I took it apart, soldered a new correct size wire, then played the “ line up and hold the brushes while I place the armature” game. Got it back together and the heater/defroster is waiting for me to install it. I’ll leave it out until I finish under-dash wiring, defroster hose replacement, and glove box install. Now on to wire harness and tank cleaning.