Steve. I'm betting you have something else going on with the blower motor. You didn't say how big your jumper wire was but if the alligator clip got hot and you blew a 15 amp fuse that fast something is not right. May need to do like said above and pull motor apart and check everything out. Clean it up and lubricate it. I have little knowledge with these heaters but have rebuilt many small motors. There are several members on here that will help you figure it out. I know Julie has rebuilt several from some past threads I have read.

 

Good Eye Bill, that's exactly what it is - a chrome horn button off a 49 Ford - fits perfect and even has Stars on it (like for a 5 Star Cab - well maybe) No one was making the caps/emblems at the time so I had to get creative.

Yep, ouch on the fuse. Is this a stock heater motor? You know it's 6 volt right? So is the switch if it's stock. Are yo still running the stock 6 volt electrical system on your 55? If not you'll either need to install 12 volt (if you have converted to 12 volt electrical) motor and matched switch, or try and find a Voltage reducer someplace. I used to recommend "Vol-ta-drop" for that, and that is how my heater power is configured, but they don't make them any more (might find one someplace dusty on a shelf).

If you still have a 6 volt electrical system, then yes there is something binding the motor or causing it to drag- might just be shot.

So three questions for you: Are you running a 6 volt positive ground electrical system or a 12 volt negative ground electrical system. Second, how many wires are ther coming out of your heater motor? And third, one wire runs to ground - do you have a really good, clean ground? Lots of rust and corrosion in those old heaters. (try running a jumper from the ground wire out to the grounding battery post then run it again just to test).

 

Bill, I was not using a jumper wire this time ratherit was an in-line fuse rated at 30 amps (12 gauge wire). After I made the connections, I turned on the switch and then the fuse blew. I agree about the heater motor and will probably tear into it a little later. Thanks. Steve

 

Hi Julie. Although the heater box looks stock, I can;t be 100% sure if the motor is 6 or 12 volts. I am still running 6 volt positive ground and since the previous owner was into complete originality, I am assuming the heater motor is 6 volts. I will have to look and see how many wires are coming out of the heater. I do know the there are 3 from the switch. I will also check the ground wire. When I initially turned it on, I could hear the motor turning for a few seconds before the fuse went. Thanks and I will report back when I can check out the wire. I think I will hold off trying a higher amp fuse for the momment and see what's going on with the motor. Thanks. Steve

 

Th evoltage is probably ok then. I'd be leaning more toward the thing needing a few drops of oil/cleaning/new brushes, or your ground is really bad on it. Maybe all of the above. Lots of corrosion/electrolysis in the old heaters.

 

I changed to the fuse to 20 amp and pulled the switch to high. Although the motor was turning between slow & fast, I could also hear thumping noise so I shut it off. The fuse held but the wire was warm. Time to clean the motor but since I have never tackled something like this before, I would like some guidance. I checked the wires going to the motor and the connection and ground wire on the firewall. They look new to me; even the back of the motor from the firewall looks so clean. Is there a way to pull just the motor without having to drain the system? Thanks.

 

OK if the 20 amp breaker held and the motor turned slow and had noises, then you don't have any gross electrical problems mismatches or shorts, you have something holding onto your blower "Squirrel Cage" or impeding rotation of the motor shaft - dry maybe. That's causing a strain on the motor and pulling extra amps trying to get it going - thus the heat. Could be a seal rubbing or the cage has come loose. But I think if you take it apart and clean it, oil it, and make sure the cage is on "square" it should be ok. Responded to your other post btw. Worst case brushes are shot and need a new motor - easy while you have it apart.

Take a pic of yor heater and post it so we will know what kind it is and can help you get it apart.

 

Thanks Julie. That's what I'm thinking as well and wil post a picture shortly. My set-up is the recirculating system that has only 2 ***** (1 for the blower and the other of defroster); it's not the "Magic Air" system. It has the heater box where the hoses connect to and a shroud connected to the left where the air exits through vents to the floor and also through the top when the defroster **** is pulled. I'll get some photos soon when I get back from brunch. My family is taking me out for Father's Day. By-the-way, Happy Father's Day to the other F100 Dads out there!

 

Julie, here is the photo of my heater/defroster set-up. This is the recirculating heater the has 2 controls...2 speed fan switch and defroster ****. Hopefully this motor will be pretty easy to remove.

 

Yep a stock recirc heater. You should have no trouble finding a replacement motor for that is need be.

Let us know what you find once you get it apart.

 

I was able to remove to motor this evening and everything looked pretty clean to include inside the compartment. I spun the cage fan and it made a few rotations. After oiling the shaft and letting run into the bearings (there was no removal cap in the back or anywhere for oil), I spinned it again and it already seemed to spin with ease. I took it to my bench and put 6 volts to it from a spare battery and it spinned really good and quiet..no thumping. Installed it back in the casing, buttoned everything up and turned on the switch....nice quite motor on both low and high speed. Of course, high speed with 6 volts isn't that much! The only thing that still has me puzzled is why my wire going to the switch and my in-linje fuse holder is still warm??? All wires going to the heater I beleive are either 12 or 14 gauge and the ground is good, clean, and tight. I am using a 20 amp fuse. Maybe the amps this motor draws may create a little warmth in the wires.

 

On the low speed there's a resistance from the switch, that may be doing it. 12 AWG should be fine. 14 is a bit small for 6 volt. My switch gets hot too if I have it on a lower setting.

 

Thanks Julie. One thing I did notice is that power to the switch is wired directly to a hot source, that is, I can turn it on without the key being on start or accessory mode. Probably doesn't matter but I will have to be mindful of this and be sure it's turned off when the truck is shut-down. I wounder how many amps this motor draws?