Re: 1939 Heater wiring

Posted by HH56 On 2016/11/2 21:38:58

You might examine the ceramic switch back very carefully. Gently try to clean and see if any of the small round indentations near three of the terminals still contain a bit of paint. The dots were originally filled with the color of paint indicating color of wire to be connected to that terminal. The fused feed goes on the remaining terminal which is connecting to the resistance wires. One of the motor leads goes directly to ground for the fourth wire.

If none of the paint has survived, I can tell you how the switch works and provide diagrams of how the interconnection is made inside with the various positions. What I CANNOT tell you with absolute certainty is the motor wire colors. The motor I took apart to replace the wires had the fabric wiring. The colors had faded so badly all were just gray and it was impossible to tell which colors went to the field and which to armature. I used the 4 original colors and made mine work using a Packard schematic of the heater connected to a Clipper switch. That is a push pull type with no function labels. The rotary switch has to be wired to have the motor run in the proper direction to match the labels. If you can identify which pair of wires goes to the armature and which to the field it will be a simple matter to connect them.

In operation, the motor reverses. One direction causes the majority of air to exit the defroster tubes and the other direction blows air out the doors with a minimum going to defroster. The armature and field being separate, are connected in series inside the switch. Direction is determined by reversing two wires which changes the relationship between the armature and field. Either field or armature can be switched so that adds a bit to the confusion. Speed control is determined by the battery voltage being connected directly to the movable contact plate for high or going thru the nichrome wire for low. The lamp in the switch is connected to the movable contact, The different voltage levels will be bright on high and dim on low.

I will wait to see if anyone has a copy of the original accessory install directions or a lead to a schematic with that type switch, or a good photo of their car. If not, and if you want it, I can post what I have with the understanding the wire colors could be wrong. My rotary version works perfectly but IIRC, Joe Santana posted a photo of his 40 switch some years back and his colors were different. His photo didn't quite show all the terminals but it looked like that installation might be different than the Clipper switch version.