I recently installed a separate 4 channel amp (a Rockford PBR300X4 PUNCH for specifics). And every time I turn the car off the rear windshield wiper will move as if i quickly turned it on as i was turning the car off. One thing I did notice is when I bypassed the "remote" wire and just connected the Battery + to the remote for the amp to turn on (I did this to make sure it all worked before I ran the remote wire) the rear windshield wiper started to move. I am still using the stock HU as the Rockford supports a High level input and I like the look of the stock radio and dont want it to look like I have any audio upgrades in the car to deter theft (I live in a city where everyone wants a nice radio and sound system).

So my main question is this, when I turn the key off for that split second is there still power stored in the amp and it somehow makes that connection as it did when I bypassed the remote wire and just used the battery and that is what makes the windshield wiper slightly move? And if so is there a way to stop that?

This is a R53 and the radio is not HK.

 

Where is the amp grounded and is the ground a good quality one with a low resistance?