Does anybody know which wire on the factory side of the harness is for the dimmer. I don't have one on the aftermarket side. I guess i have to use a wire tap to access it on the factory side. I had to do that something similar with connecting the remote turn on to the the pink wire on the factory harness (bypassing the aftermark part) in order to get my factory amp for the 10 speaker system to come on.

 

should be a grey wire. there is two grey wires on the factory harness.
one for the front left speaker and the other is used for either the dimmer or illumination.