Three dr. heater wires ?

[Bob NH]

I'd be pretty sure that some on here have been all the way inside the 3 dr. heaters ? I have one all apart and it appears all four wires in the motor are the same color. These are badly frayed especially where they come through the housing. I would like to put in new wires and wondered what would be correct color coding for identification when going to an original heater switch which has fast and slow indirect and direct positions ?

[rotorwrench]

Usually there is still some color on the wire inside the motor housing but a lot of water is under the bridge since that part was nice and new. It is a multi speed motor and a person does need to know which wires go to which coils and which is the ground path.

Kube may be able to answer your question if this is from a 39 or 40 vehicle.

[19Fordy]

Have you done a search for "heater wiring"? i'm sure this has been covered before.

[Seth Swoboda]

I just did some work on the heater in a '47. I had the same problem. I did not replace the wiring but needed to know what wire went where on the switch. Luckily with some closer inspection, I could vaguely identify the color of the wires. There was some luck involved and I got it all wired up on the first try.

Take a real close look and you might be surprised that you can eventually figure out the color codes.

[Darrell S]

I was able to wire my heater on the 48 using a diagram labeled 39-40. Marked as follows,

Motor outside field-yellow
forward brush-red
reverse brush-brown
motor inside field-green-to ground

Hope you find this helpful.

[JSeery]

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I copied these a while back, not sure if it helps or not?

"I am looking at a heater switch wiring diagram. There should be four wires coming from the motor. If you look at the back of the switch there are three contacts around the edge and an oddball contact with a resistor. Starting with the odd contact this is your power wire, it should be red with a black tracer and it goes to the circuit breaker up at the top inside the firewall. For the other three the red wire should be a the nine o'clock position, the yellow wire at the 12 o'clock position, and the brown wire at the three o'clock position. The green wire from the motor should be attached to any convenient grounding spot. This assumes of course that you either have color coded original wiring or a new motor wiring harness from a reputable vendor. If you have wiring that someone made up you will have to figure out which wire is which. According to the diagram green is the short field wire, red is the forward brush wire, yellow i
from the photo that you posted, the wire from the ignition switch should go to the top terminal. I cannot determine the color coding on the other wires, so I cannot tell you where they belong. Try the following procedure to get the wiring sorted out. There are 4 wires coming from the motor. The yellow and the green wires come from the field windings and the red and brown wires come from the brushes. If your colors have faded so they all look yellow, I use an ohm meter to make an initial guess as to which wires are from the brushes and which wires are from the field and then I use a battery hooked up to a switch to determine which of the wires used for forward and reverse direction of the motor. Usually you can see a little of the green cast on the green wire and the red color on the red wire. If you connect your ohm meter between the green wire and the yellow wire, you will have near zero ohms resistance. Any other wire will show an open condition. The reading will not vary when you rotate the motor shaft. When you connect the red and brown wires, you will have more resistance than the field connections showed and it will vary slightly as you turn the motor. To check the motor out without a switch, connect the green wire to the POS terminal of a 6 volt battery ( a lantern battery will work for convenience), then connect the yellow (field) wire with the red (brush) wire together and then the remaining brown (brush) wire to the Neg terminal of the battery the motor should run. If you are using a lantern battery, the motor may require some assistance to start. Three of the wires from the motor will be attached to the switch according to the colored dots next to the terminals on the switch, the green wire will be attached to ground and the terminal with the black dot will be attached to a 6 volt source. The red and brown wires control the direction of the motor. When the switch is in the HI Direct position the fan should be blowing air through the heater core. On 1940 heaters this means that the motor is turning counter clockwise."

[Bob NH]

I'm kinda snickering to myself here. I missed the colors on 16 out of 25 plates when in the service in the tank core before being shipped overseas ! Captain said,"we don't want you shooting at our tanks, so your staying stateside "! So you might say identifying colors is not my strong point. These particular ones do appear all the same even to a couple other guys. The last comment is helpful and thanks