1940 heater

General topics, not covered elsewhere, of all things Packard.
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Joined: Tue May 15, 2012 2:52 am

1940 heater

Post by RCMerritt » Tue Dec 04, 2012 5:46 am

When I bought my 1940 120, the heater wires (4 of them) were present but disconnected, and no heater switch.
No surprise, it didn't work. :D

I've now removed the heater and can see the motor needs to be rebuilt, but it is
riveted to the heater housing, and requires more than what I want to do.
I am looking for someone to
rebuild the whole heater
Any suggestions?

Eventually I'll need a wiring diagram
or instructions on what to do with the 4 wires.
A review of the factory service manual hasn't provided answers.
Any suggestions here?

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Joined: Sun Jul 19, 2009 12:55 pm

Re: 1940 heater

Post by jacko » Tue Dec 04, 2012 1:54 pm

Bob, When you say rebuilt what are you thinking? Complete disassembly, bead blast, motor tear down and fixed ? Send me some pictures at jacko@purdue.edu and maybe I can help.


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Re: 1940 heater

Post by lc3packs » Sun Jan 13, 2013 4:12 pm

Funny, I bought our 1940 160 in the same condition. No heater switch and the wires are not visable. I am going to look for the wire and connect it to the ignition switch I bought on ebay and say a prayer that it will work. I will put a fuse between the switch and the heater just in case!

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Joined: Sat Jul 11, 2009 9:02 am

Re: 1940 heater

Post by JWL115C » Mon Jan 14, 2013 8:41 am

I believe your heater-defroster has a 2-speed reversible motor operated by a special switch that selects the heat or defrost mode and speed. In one direction the fan blows heated air into the passenger compartment and in the other up to the windshield through tubes and outlets in the garnish molding.


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Re: 1940 heater

Post by Howard56 » Mon Jan 14, 2013 12:52 pm

Anyone have any ideas on how many model heaters had the reversible motor and if they are alike electrically. I have this unit pictured that I figured out how to wire so it works. Made a schematic for one style switch. There are apparently at least 4 switch styles though. The wire colors on this unit are the old fabric and faded to almost the same dirty brown shade so it's hard to make a good color judgement.

To confuse the issue, looking at other switch photos posted I find apparently there are either more ways to wire a single unit than one would think or there is more than one unit with wires of different colors or functions. I take it with the non response to the first posters question there are no real schematics floating around.
Prewar SuperDeluxe Heater.jpg

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Re: 1940 heater

Post by jacko » Tue Jan 15, 2013 12:25 pm

My 1940 110 series 1800 coupe came with a hot water heater and switch. The switch is radial and is a double pole, double throw switch to use rectilinear terminology. So, the motor is reversible and is two speed. The lower speed is accomplished using nicrome resistance wire wound around a 1/8" ceramic rod. Both forward and reverse switch settings have a low speed (<6v) and a high speed (=6v). When I took the motor apart it appeared never to have run since the commutator was like new. I discovered that the carbon brushes had never been seated correctly on the commutator and so the motor had never run-- probably from the very beginning when the car was new. The car was originally from Florida so that may answer why the heater was never fixed! Once I seated the brushes correctly, the motor ran fine.

After installation in the car I noted that the main feed wire (which was new and I ran the wire from the ignition switch to the heater wire bundle on the back of the switch) would get hot. So I measured the current flow to the heater and found that the heater uses 18 amps at 6 volts. So I installed a new power on/off switch upstream of the Packard switch and a 20 amp fuse (just in case) and a heavier feed wire. Now, I don't use the original heater switch since it looks rather fragile and irreplaceable, just the new single pole single throw toggle switch from the hardware store. I keep the Packard heater switch in the on forward position and simply turn it on with the new toggle switch which is hidden under the dash. I found that the defroster is very anemic although it does defrost an inch or so above the outlet at the base of the windshield, so I hardly ever use the heater fan in the reversed position. The wire bundle to the heater motor has four wires and the electrical circuit can be figured out by using a double pole, double throw swith like you would get at a hardware store. One throw would use crossover wires to get reversed voltage polarity and thus reverse rotation. To get low speed you would have to install resistors.

Bob Jacko

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