Bob, The two wires (green and purple IIRC) are neither power nor ground. Each is BOTH power and ground. But not at the same time ; -) For UP, the green is +12 and the purple is ground. For DOWN the green is ground and the purple is +12. Or do I have that backwards? Actually, it doesn't matter. Just DO NOT hookup a ground wire to the motor case! I wouldn't use a battery charger to test the motors. It might work, but battery chargers put out really "dirty" DC voltage. Meaning that the AC voltage is chopped down and rectified but, if you look at battery charger output in an oscilloscope, you'll see that it isn't steady DC voltage. Use jumper wires and your car battery to test, but be sure to make all final connections at the motor. Sparks at the battery can cause a big boom. Pete in PA From: "Robert Hanekamp" <bobsmopar@xxxxxxxxxxxxxx> I am restoring my 68 Imperial crown convertible and I have all the windows motors out and I want to test some off the extra ones that I have and I want to lube the ones that are out. There is two wires that come out off the motor is one of these a ground and can I use a battery charger for power .