I have been there/ done that with the Mopar 4 pin ecu’s not working on the 5 pin harness. Ive also had lots of 4 pins work with a 5 pin harness and dual ballast. I’ve also wired in a single ballast to a five pin box and the box overheated and killed the motor. Let it cool off and it would run till it overheated again. Then again some worked. Kim
