I installed a Pac bypass when I installed my W200 in my 05.I moved the w200 to the new 07 with the same harness and made no changes to it.The bypass worked fine in the 05 and with it in the 07 its not working.Any way I can test the bypass?Do I need to reset it in some way?

 

no you shouldn't need to re-program it, it doesnt have any constant power wires so its not like it has a memory to save. when i took it out of my old car, i just wired it up again and it worked fine. check your wiring again.