Now you have renewed my interest.

I'm embarrassed to admit I've misplaced (certainly not discarded) that window motor after searching for an hour Sunday. Nothing screws with my head more than something I've hidden from myself.

My guess, having never opened a window motor, is the device you're asking about is a positive temperature coefficient (PTC) thermistor used as a resetable fuse with small DC motors to protect against overheating with locked rotor current. I know the central locking actuator motors use them, but in those they are shaped like a dime (and can be replaced by one) silvered faced ceramic disks. The resistance rises when they heat up.

If the device you have is in series with the motor windings, you might be able to bypass it and have a zero-dollar fix. Or it may just need its connection cleaned. Meanwhile I'll give that search another go because I want to see for myself, and I tire of reading reply posts in this forum made up of speculation.
--
Art Benstein near Baltimore

Working people frequently ask retired people what
they do to make their days interesting.

Well, for example, the other day, Mary my wife and I
went into town and visited a shop.

When we came out, there was a cop writing out a parking ticket.

We went up to him and I said, 'Come on, man,
how about giving a senior citizen a break?'

He ignored us and continued writing the ticket.

I called him an “***hole” . He glared at me and started
writing another ticket for having worn-out tires.

So Mary called him a “s*** head”. He finished the
second ticket and put it on the windshield with the first.

Then he started writing more tickets.
This went on for about 20 minutes.
The more we abused him, the more tickets he wrote.

Just then our bus arrived, and we got on it
and went home.

We try to have a little fun each day now that we're retired.

It's important at our age.