Just got her yesterday, 8-26-14, 1984 300TD, and trying to make her right. Both front windows don't work. Have 12 volts to both screws on terminal block on door. Removed power side wires and used a good battery to power. Sparked , no movement, so I'm assuming motor has a dead short. Anything I'm missing? Learning a lot through this site and any help will be appreciated.

Update. Pulled both motors they work intermittently. Worked forward and backwards so I reinstalled and got nothing. Pulled again and bench tested. Would go one way with power supplied. If I disconnected power and re applied it just sparked. Reversed wires and it would spin. Reversed wires again and it would spin a time or two then short again until I reversed wires.
That all being said I am looking for two good motors. Anyone have a couple lying around?

One more question. Looking at the two motors in front of me it seems they are identical except for the side the wires are attached. Are they side or front/rear specific?
Also I pulled the motors only. Not the gear set. Just the motors with what looks like a worm drive shaft.

Further update..
Pulled regulators they were in good shape. Reexamined motors. They would sometimes spin freely when jumped with a battery, sometimes not. When turning by hand they were a little stiff, especially when turning one way and not so much turning the opposite. Got very stiff when turning and pushing shaft towards the motor housing. It turns out the bushing in the bottom side of the motors were very stiff. I'm not sure of their construction but the harder I pushed towards the housing the stiffer it turned. Not sure of the prudence of this but I squirted oil in both of the holes on the bushing side of the motor. Chucked up the shaft in a cordless drill and spun it in both directions a few times. Felt much freer when turning by hand. Reinstalled and windows now work. For now. Probably not a long term fix.
The worm drive shaft on the motor turns a perpendicular gear which operates the regulator. When the motor turns in one direction ,say clockwise, the shaft wants to crawl one way or the other. Say away from the housing. When the worm drive shaft turns the other way it crawls the opposite way. Ever so slightly in either direction but enough to create enough drag/friction to stop the motor when it's crawling toward the bushing. .
Hope this helps someone save some diagnosis time.