TC
Just my 8 cents worth here;
Did the original PE work?
Do you know the original PE cable is good?
Is the original cable still clamped at the end of the car door header?
When you say you disconnected the GK, ( and the fuse still blew) did you also disconnect the original wiring from their termination points to eliminate a possible back feed to the controller? I mean like disconnect the whole darn thing.
Did you abandon the PE bypass switch on the COP?
Hope you gotter figured out today.
