I have a '70 chevelle concours wagon and am having issues with the tailgate power window. I've replaced both the switch and the relay a couple of times each, but the switch keeps shorting out. I have a buddy who owns a hot rod shop try and work on it, but he couldn't understand why it keeps shorting out. Just wondering if anyone has had this kind of issue. There are no visible loose or broken connections. Right now the way it is I can connect the switch to open or close the window, but then I have to disconnect the switch otherwise it'll start smoking and there goes the switch and or/relay.
could the switch itself be shorting to the dash? I've seen where an old metal switch shorted to the dash panel where mounted. I'd try to insulate it with a rubber washer or even electrical tape to see if that helps. I bet its grounding to metal somewhere its not supposed to be (probably close to where it smokes)
Use a multimeter and see if you have a full 12VDC at the switch before you hook it up. Then hook the switch up and quickly see if the other sides of the switch have voltage. The motor might have a short as well, causing the switch to have too much current run through it. This would cause the smoking effect as it would over heat the switch. A loose ground wire in the tailgate might be a cause. Also if the power to the motor has a bare spot and touching the metal @ tailgate. I know cracking the tailgate open is a pain in the butt though.
