39 blower switch

[Tubby]

I am trying to refurbish a 1939 hot water blower switch. I believe it is missing a resistor (or 2) that I think provides the different voltage for fast and slow blower speed. Does anyone know if there was one or two resistors; what were their resistance value and which terminals does it (do they) attach to (A, B, C, D in attached picture)?

 

[TerryOH]

One resistor of 1.0 Ohm. connected from B or C (they are both the same point electrically, common to each other) to A or D (they are both the same point electrically common to each other) The resistor appears to be rather high wattage.

 

[Tubby]

Terry,
Thanks for responding. Current state of my switch: yes B and C are common, but A and D are isolated from each other and from B and C. (I have included a picture of switch plate from the other side, same labels.) I do see remnants of wires under each terminal on the top side of the plate (original picture). Perhaps A and D were commoned with a wire?

 

[TerryOH]

I believe my switch is slightly later in vintage. Your switch appears original to 39 & 40 below are a couple of switch diagrams. Your switch does not appear to use a resistor.

 

[Tubby]

Terry,
These sheets are very helpful. As I indicated, there seems to be remnants of wires under the 4 terminals I labeled as A, B, C and D. Your sheet shows 2 resistors attached to those terminals. I think these are to provide reduced voltage to get reduced blower speed. I just need to determine the resistor value and how to attach new resistors. Thanks again.

 

[TerryOH]

I believe the resistor is not shown correctly. If both ends of the resistor were wired as shown the resistor would be shorted. One end of the resistor is connected to the black battery terminal and the other end is as shown.

 

[Tubby]

Terry,
Can you direct me to where I can purchase these installation instructions?

 

[TerryOH]

You should be able to print the two pages I posted above. Send me a PM.