Topic: Heater Motor Questions


pech33    -- 06-06-2021 @ 3:45 PM
  It appears that the heater motor is toast, I can't get it to budge. It spins by hand, but not on it's own. My question is this: single speed motors are offered online , my motor has four wires, I assume one power and three speeds. The switch has OFF and three clicks to the right, so I assume three different speeds. Am I correct? Any idea on who could rebuild this puppy? It is highly possible that I didn't give it a correct "hook-up" to test it. I grounded it to the block and hit the power wire to the negative terminal on the batter and then to the positive terminal after it didn't budge. No sparks, no nothing.


Also, now that the heater is down, is there a problem if I connect the heater hoses together and let it recirculate through them until I get the new heater motor?

Thanks in advance.


carcrazy    -- 06-06-2021 @ 9:19 PM
  There is no problem with you hooking up the two hoses to each other allowing engine coolant to just circulate through them. The only 6V heater motor that I found is offered by MAC's Auto Parts. It is a single speed unit and not listed as fitting a 1940 Ford. It claims to be a universal motor that will work on 1941 and later Fords. This unit could possibly be made to work with minor modifications.

You might be able to get your current motor repaired in your area. Look for an electrical repair shop that does starters and other motors.


TomO    -- 06-07-2021 @ 7:44 AM
  You did not test your motor accurately. All 4 wires must be connected to either a ground or a voltage source. It sounds like you do not have a correct switch for your heater motor. The correct switch has OFF in the center position and HI and LOW Indirect flow when turned to the right. Turning the switch to the left should give HI and LOW Direct heater flow.

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.

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

Your green wire has a spade connector, so you are halfway home in identifying the wires.

The most common cause of the motor not running is because the brushes are worn. If you take your motor to a shop for repair, buy a new wiring harness and have them install it for you. I would opt for the repair option rather than install an aftermarket motor that will not fit inside the heater correctly.

Let us know how you made out.

Tom


pech33    -- 06-07-2021 @ 9:26 AM
  Here is the switch, it says: S-F with DEF. underneath it and on the right side is says F-S with HEAT below it. I will attempt to pull off your test. Thanks.


pech33    -- 06-07-2021 @ 9:33 AM
  OK, I think I understand the switch. Off is in the center, left has S for slow F for fast for the defroster. Right has F for Fast and S for slow. F is the first "click going left or right with S being the second option.


40 Coupe    -- 06-07-2021 @ 2:36 PM
  The switch is from a hot water heater and appears correct in appearance and the operating knob is correct. Two of the wires in the motor are the field, two wires are the armature. Can you use an Ohmmeter?
The wire with the split spade connector is ground it goes to one lead of the field windings and is green. To find the other field wire use your ohmmeter on the the green wire and check the other three wires for continuity that wire should is the second field wire and is yellow.
The remaining two wires are the motor armature. If you connect the ohmmeter across them you should also find continuity. one wire is red and the second is brown.
Connect the brown wire and yellow wire together then connect battery - (Negative) to the red wire and battery + to the ground wire with the split spade. The motor should run, or try to, if so it is good.
You can buy another wiring harness for the motor from several of the wiring suppliers.


This message was edited by 40 Coupe on 6-7-21 @ 2:52 PM


40 Coupe    -- 06-08-2021 @ 5:05 AM
  Wiring diagram to the switch below

This message was edited by 40 Coupe on 6-8-21 @ 5:17 AM


pech33    -- 06-08-2021 @ 7:19 AM
  Thanks . Excellent. I have a new harness on the way and I have two local sources that can rebuild the blower motor. It is amazing to take the heater apart and I marveled at the engineering of the day (1938+) in how they designed the parts and pieces to all fit together in a relative small package to heat the cabin. It reminds me of going through a WWII airplane and looking at the simplicity of the systems and the ingenuity of the designers. I have had this car about two months and I am fascinated with it. The vacuum system on the top is on the agenda. It tries to lift, but I think the canisters need attention. Once again, simple but ingenious. I should have bought one of these 30 years ago instead of my bubbletop.

Pat’s 40 Ragtop

This message was edited by pech33 on 6-8-21 @ 7:24 AM


pech33    -- 07-19-2021 @ 12:25 PM
  Just finished the heater. Found the paint at Lowes, Gloss Pewter Gray. Instead of trying to paint the three red stripes on each side, found pin striping tape, 1/8" at O'Reilly's for $2.00. It is not being judged so I don't care if it is absolutley correct. The switch still has an issue. It works on Defroster F & S (fast and slow I guess) and the Heater only works on F. I assume the switch needs to be taken apart and looked at. I doubt I will be using the heater with the top down. If it's raining, I'm not driving it.

Pat’s 40 Ragtop


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