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So for today's Packard Mystery I present the tale of two Packard 6V rear defrosters.

So years ago when I was cleaning out Dan Yocum's sheds after his passing. I discovered a 6v Packard rear defroster. The housing was crumbled, but the blower motor and heater element were there as was the grille that mounts topside on the package tray. We shall call this the "Shed" one.

Fast forward a couple of years, and I see another one at the PI Swap meet, with a good housing, and with a sticker on it that says "Works 6v". And for a couple of dollars (literally) I acquired one in much better shape, but no grille. But not a problem, since I have the grille from the other one I can use.

Fast forward to now. I figure I will check out the "works" one and see if it indeed works, and I want to know how many amps it pulls so I can figure out the right 12v>6v step down I am going to need to use it. So I hook it up inline with my amp meter and it works and is pulling about 3amps. But the unit never blows any hot air. Curious, I think. So I look at the "Shed" one, and I notice that one has 4 wires coming out of it, but the "Works" one has two. So I pry to the top plate off of the "Works" one to see what is going on. Low and behold, it's missing the heater element. Not only that, but it doesn't even have any holes in the housing where the element was mounted, or for the wires for the element pass through! I look at both the "Shed" one and the "Works" one, and besides that, they are identical. Same exact motor numbers, same dimensions, same everything. Except the "Works" one looks like in never had a heater element.

So what the heck is going on here? Did Packard may two different ones? What is the point of a defroster without a heating element? I mean I can mount the element in the good housing and have a fully working defroster. Just trying to wrap my mind around why one has an element, and the other one doesnt.

The "works" one is on the left, "shed" one is on the right.

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Interesting question. Hopefully someone has a dealer accessory page with numbers and prices that could answer the question.

If the one with a heater can be tested I'd be curious how much extra load that element requires since they were suggested to be wired in parallel with the front blower.

If the deteriorated unit can be repaired enough to be usable I have a grill you can have.

I have a grille for one of them. The other one is beyond repair and the motor is kaput. So it will take the parts for both of them to make a good one. But, thank you for offer. :)

Not sure why one is missing the heater element. Perhaps it was built incorrectly? A rear defroster with a heat element to me would be non-functional. So can't understand why one would be made this way unless it was a manufacturing mistake.

Oh, and to answer your question. The motor pulls around 3-4amps. The heater element pulls about 4amps. All of this tested at 12v. I was thinking of using a micro switch off of the defroster lever to control a relay for that defroster circuit.

I suspect the one without the heater was a later model. I recall seeing a rear defroster on a GM car when I was young that just blew cabin air across the rear window to defrost it. Packard probably found it unnecessary to add the electrical load for a heater in their defroster to a 6 volt system.

The housings appear to be different. Possibly the one with OUT the heating element was used for an air conditioned car. That is it was used more for DEFOGGING than for defrosting.

In extremely hot humid climates, winddows can fog up REAL FAST!! SSO turn on AC and turn on the "defroster" which in this case is not a defroster at all but just a force fed blast of very dry air from the AC evaporator.

But do note the differnce in the housings. Maybe have to think about that one for a while. Best guess i havee is that one is for actual deFROSTING while the other is for deFOGGINg in hot humid weather.

Therefore perhaps the variation in the housing design.

Housings are the same. One is just very damaged and the angle from the photo makes them look different.

My mid-'60s Imperials do not have a heater element either and work well even for defrosting as long as the interior has warmed sufficiently. Perhaps that's the same idea here with the Packard unit. (My Imperial now has the rear A/C - in addition to the front A/C - so no more defroster!)

I can see one without a heater element working well as a "defogger" to clear the inside of the window, but if the window was iced over, it would take a very long time to defrost an actual window.

I think the plan for me, is to move the heater element over to the good housing with the good motor. I will then wire the element and motor in series as opposed to parallel like originally connected. That should take care of the 12v-6V issue without having to use a step-down resistor. I'll mock this up on the work bench and let it run for awhile to make sure there are no issues with it.

BigKev, I think what you have there is a Defogger and a Defroster accessory items. I have a few of them from different makes and I'll look at the box to see if there is a difference in wording as the blower assembly is exactly the same as the Packard photo (the reason for buying them). I think you would be on the right track to make a switch to turn the blower on as well as turn the heating element on/off because I think Packard would have it wired directly to the heater switch. That would definitely put a load on the wiring.