I'm working on my 1970 coronet. I have a six amp 12 V charger connected to the black and red battery terminals (No battery connected). When I connect my three speed wiper switch and turn it on, the wipers function in all speed positions and parks when in the off position. The 12 V lead gets hot and the heat breaker inside the switch pops. I am expecting that this means I have a ground issue. I grounded the switch body to the dash. No good. With the switch disconnected, I tested all the wiper motor leads at the switch connector. I found that the brown and blue leads have continuity with chassis ground. I disconnected the bulkhead connector and tested the leads on the motor's bulkhead plug. The brown and blue still had chassis ground. The bulkhead terminals, showed no ground. I rebuilt my wiper motor myself. It tested fine. All wiring is new and correct gauge. Any ideas if those two wires are supposed to be grounded or why my switch is roasting?🔥🔥🔥