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-   -   rear window defogger motor (https://forums.maxperformanceinc.com/forums/showthread.php?t=884770)

AROWHED 03-27-2026 12:41 PM

rear window defogger motor
 
3 Attachment(s)
Looking for a new motor for this defogger, the fried original pulled from a car that sat for years is beyond saving. Sealed motor case, 1/4" shaft, but what RPM and HP to search for?

Also, did these defog well? It appears to simply draw cabin air in and blow it back out, no dried or heated air source besides cabin air. The motor is external, mounted to the that duct, and on the underside of package shelf in the trunk.

Bill Hanlon 03-27-2026 08:29 PM

Looks a lot like this one: https://classicparts.com/chevy-gmc/c...-motor-12-volt

Goatracer1 03-27-2026 09:57 PM

You should be able to find a small 12 volt motor that you can use to replace yours without too much work. No they don't work like a modern defroster but they were better than nothing. Are you planning on using your car in the winter?

bret 03-28-2026 08:08 AM

I have a working 70's rear defogger that works and looks the same as yours shape and style wise , maybe pm me as I have no idea how to post pictures in a reply

rustyrelic 03-28-2026 12:28 PM

Is there enough left of the old motor to rebuild it? Any starter/motor rebuilders nearby?

AROWHED 03-28-2026 01:15 PM

Thanks for the replies. The armature windings are completely fried, bearings rusted up, lots of burnt and rusty crap came out once case was split open, not worth screwing with. I ordered the one Bill Hanlon linked, it is very close dimensionally and surely can be modified to work, although it is listed as a heater motor, so I wonder if it may be too powerful with the tiny little metal fan this defroster has.
Not that it will get used much, I don't drive in winter or rain...just curious how well they worked at all considering a rear window defroster was an option back in the day these cars were new and probably got used often. It is better than nothing, as Goatracer said.
Bret you could list yours in the classifieds of this site, someone will want it. I appreciate the offer.
For those wondering, the original motor is stamped 13.5V 5044597 DELCO APPLIANCE ROCHESTER NEW YORK USA.
Now to dig around and figure out where I put the dashboard switch.

AROWHED 04-02-2026 08:31 PM

1 Attachment(s)
Got the motor, a bit larger than original and needed a few slight mods but it works well, and moves a decent amount of air. Problem now is I can't tell where the assembly mounts on the package shelf. Seems like driver side but long ago my 65 GP was cut out there for a 6 x 9 speaker. Anyone got a trunk view pic of your 65-66 with a rear defroster installed as Pontiac would have done it?

MPKind 04-14-2026 02:03 PM

I can snap a picture of mine installed. It is on the driver's side on my Catalina that has a square and circle hole. The 6x9 is on the pass side for the single speaker. Not sure what the factory holes look like on a GP with the preinstalled rear speaker grill.

I don't think they do much more than improve circulation of the warm air that makes it way to the back of the cabin.

AROWHED 04-17-2026 09:03 AM

Thanks Matt, I did get it installed finally, as the GP is same as Cat in this regard but the pre-punched circle and square were long gone, cut out for a second 6 x 9 speaker before I bought the car. Moved the 2nd speaker into the back seat center grille, sound is a bit heavy on the right ear now. Got it wired up, has two speeds through the dash switch. Doubt it ever gets used as intended but at least now the GP has another option. You could post the photo just for the record. Thanks again.


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