The Stovebolt Site Forums The Shop Area The Electrical Bay '54 Harrison heater fan hookup?

Hello,
I have disassembled, cleaned, checked and greased the heater unit which came with my '54 6 Volt 3100. The current draw of the motor has dropped from erratical 8- 10 amps with poor and noisy performance to about 5 amps. It runs now quite and steady and produces a steady and strong air flow.

I read here that some had difficuties with the springs and brushes in the motor. I fixed the springs with small crocodile clamps all the way into the brush guides, placed the (old and worn, replacements ordered) brushes in as far back as possible until the armature was in position. Then I retracted the clamps and fixed the spring positions (tilted ends) with a piece of thin steel wire. That went well and I found it pretty easy.

Since the heater unit was only mounted in position but wasn't hooked up, neither electrical nor to the cooling system, I have to figure out how to do this. I don't have any problems with the water side, but the electrical side gives me a bit of a headache (although I once was a proper trained non-car related electrician). The oldcarmanualprojects page does not working at the moment so I don't have access to any accessories related literature and a forum search didn't bring up all answers needed.

So I start out with some questions:
I read those 5 amps on the indicator of my battery charger while testing the motor. This number seems pretty reasonable to me, but is it really ok?

There is a off-low-high switch with a resistor coil on a ceramic tube mounted to the car, but also not hooked up. The ceramic tube won't stay inside the resistor. That seems to be a mechanical problem, but I don't have the least of a clue how to adress this. Can you please give me any suggestions?

"Use a fuse and wire accordingly" is a no brainer on electrical accessories and based on the numbers I gathered while checking with the battery charger I would select a fuse of 10 amps, which will blow eventually on a blocked up motor as well as on a short but won't blow if motor condition decreases a bit. Is this good, or am I way off from the original or experienced numbers (to high/low)?

And the last question: I would like to have the switch hooked up to the ignition switch, so that the heater fan is turned off with the cars engine. Can I simply put this high current to the ignition switch or do I have to use a relay? I don't like the idea of neither a dead battery due to forgetting switching off the heater fan, nor frying the ignition switch with to high current...

Thanks in advance for any hints, suggestions or instructions.

I recently reconditioned the Harrison heater in my 54 3100. 10 amp fuse should be okay. There should be a fuse holder on the back of the switch. That should already be part of the circuit and all you need to do is plug in your new 10 amp fuse. You can hook the power supply to the ignition switch. That is how mine is wired and I have not had any issues. Not sure about your switch problem with the ceramic tube. Maybe a small drop of silicone from a hot glue gun? These do get hot from what others have posted and it could get hot enough to re-melt the glue. I am assuming your truck is still the original 6v system and has not been converted to 12v. If you are 12v the original fan motor will not last long before it burns up. The original switch will work with 12v. You can order a replacement 12v motor from AutoZone. Below is a link to the replacement motor. They cost about $30.

Link to AutoZone Electric blower motor

Thank you Dave,
Yes my truck is still original 6 volt and I will keep it this way. I haven't touched the switch until now, except for putting the ceramic tube back when it fell out (more than once ).

I will unmount the switch and check for function and the fuse holder tomorrow. Maybe I can then also figure out how the ceramic was initially fixed to the resistor. If not, I will look if I can bend the resistor wire enough to prevent the tube from slipping out, since I have no other idea what else to do.

The ceramic tube is part of the insulator that reduces the fan speed at the lower switch settings. It is probably damaged and shouldn't be used. HOWEVER - the switches are original, rare, and extremely cool looking.

The heater fan switch in my '54 3104 doesn't work. I hid a modern three-speed rotary switch under the dash to control the fan speed. The switch gets very hot when operated on lower speeds, so mount it where it won't damage paint or wiring. Everything looks original

> PHOTO: Non-working Original Heater Switch <

> PHOTO: Hidden New Heater Switch <

> LINK: 6-volt universal heater switch
https://www.brotherstrucks.com/47-54-UNIVERSAL-HEATER-SWITCH-6-VOLT/productinfo/HSW5406/

> LINK: 12-volt universal heater switch
https://www.brotherstrucks.com/47-59-UNIVERSAL-HEATER-SWITCH-12-VOLT/productinfo/HSW59ST/

- Lonnie

Nice job. It looks good. I see you have the upgraded fresh air Harrison Heater. I have the recirculating model, but everything else is the same. Switch, wiring, etc...

Hi all,
I have an update on my heater and switch. I seem to have a working original switch in good condition. I found the fuse at the back and it came with a quick responding 14 amps rated fuse (Killark SFE14). That also seems ok to me.

I carefully stretched the resistor windings a bit, to tighten the windings. Now the ceramic tube sits well fixed, even when the windings heat up. And they will heat up: I measured with my infrared gun 110°C (230°F) after a few minutes running at low speed.

The heater fan motor will work rather quite at full speed. At low speed it is developing a slight irregular rattling noise the source of which I can't detect. Since it is not very loud and will not be audible when the engine is running I think I will live with it that way.

I am happy it all worked out well. Now I have to wait for the new heater hoses and fittings to put all together and mount it in the truck.