The Stovebolt Site Forums The Shop Area The Electrical Bay A Heated Paddle Switch for your AD Heater

Been using the Deluxe Heater in my 1950 a bunch now that the weather has gone sour on us. And am finding that the paddle switch makes a great hand warmer, to good in fact.

I’ve heard people voice their concern over this before but never paid much attention or gave it much thought. Mostly because I thought that the wire wound resistor on the back of the AD paddle switch was a voltage-dropping resistor to slow the motor down in the LO speed setting. I just assumed that the motor was a 6v motor and on high speed was wired direct and took the full 6v.
Obviously I was wrong because this little sucker gets hot enough to burn ya BBBBAD, whether it’s in HI or LO. So I guess for some reason it’s in the circuit no matter what the switch is set to.
WHY is zat???
Denny Graham
Sandwich, IL

I dunno but i toasted my fingers just the other nite too.
I saw it glowing and thought a bulb had fallen from the gauges and when i felt around to try and find it,,,I FOUND IT!!!
Im sportin a couple nice blisters on my finger and thumb tips.

That switch gets hot -- very hot -- and that is what it's supposed to do.

I don't know how to explain it so that I'm not sounding like a high school physics teacher, but I'll give it a shot.

The law of conservation of energy states that you can't destroy energy, you can only convert it into other types of energy.

So, what's happening in your switches is that law in action. You've got a certain amount going into the switch, a lesser amount coming out of it, and the rest of that electricity has to go somewhere, so it turns into heat energy.

It's normal... but if you start melting things with the switch I think I'd find a different switch.

Denny,

When the switch is all the way up it is in the off position (I'm sure you already know this). Then there are 3 detented positions for High, Medium, and Low. The first detent down is for high. The resistor is bypassed and the full voltage is applied to the heater motor. In this position the switch should not be any warmer than the wires carrying the current to the motor. The second detent down is for the medium speed. This connects to the center tap of the resistor and only half of the resistance is used to drop the voltage being applied to the motor. The third and last detent is when the switch is in the full down position. This switches in the full resistance of the resistor to drop the voltage further before being applied to the motor for the low speed. The switch will get warm from the heat given off by the resistor, but it should not get to the point of being hot enough to burn your fingers. It is the resistor itself that gets very hot (only in low and medium speeds) and should not be touched.

If the switch gets too hot to it has to be coming from internal resistance in the switch itself. This can be caused by corroded or tarnished contacts, loose rivets, and poor contacts in general. I have all of these conditions in my switch and have disassembled it for cleaning, repair, and rebuild.

Well Jim, since ya don't have any year, make or model of your truck listed I have to assume that we're talkin’ bout two different animals. This is for a 1950 delux heater, two speed.
The paddle switch only has OFF-HI-LO positions on it. As I said in the original post, "I thought that the wire wound resistor on the back of the AD paddle switch was a voltage-dropping resistor to slow the motor down in the LO speed setting. I just assumed that the motor was a 6v motor and on high speed was wired direct and took the full 6v".
Meaning that the wire wound should only be in the circuit in the LO position.
The point of the post is that it is hot even in the HI position.
It’s a simple matter of pulling the switch out and checking the circuit, I just have to get time to do it, kind of busy this time of year. Just thought someone here might have analyzed it before me.
Denny Graham
Sandwich, IL

Denny,
I have a Johnny Cash truck. It is titled as a 53 but the Huck brakes and other small differences on the cab and chassis tells me that it is a 50, although the motor is a 53. When I got the truck it had a partial and badly done 12 volt conversion. It had a fresh air delux heater but the control valve and heater motor switch were missing and the motor was disconnected. I found a control valve and three heater switches at a junkyard. The valve and switch I'm using came from a 50 Chevy 1 ton. The other two switches came from a 51 and 53 GMC, but except for the color they were all the same. I rebuilt the control valve (you have to calibrate it for the off position when reassembling) and none of the three switches worked right. I had to disassemble all three switches to get a good one. I replaced the heater motor with a 12 volt motor. I hooked a battery charger to one side of the switch and the motor to the other side. I have three speeds. I ran the motor for over an hour at high speed and the switch never got warm. At the medium and low speeds the switch got warm from the resistor but not overly hot. My switch is the paddle type and is maroon with white lettering that says HEAT.

I would add that my switch in the firetruck got hot and I saw smoke coming from it the first time I used it. Now that I've used it a few times it still gets hot but it doesn't smoke any more.

if getting hot to point of burning fingers replace...doc