Alright, I have read thru the posts however I have a similar but different problem. My lights flicker constantly(01 Monte Sport), I have added numerous grounds to body, frame and engine. I do have an isolator switch which connects to two additional batteries mounted in the rear and am using 2awg cable for the entire setup (inverter in the rear). I do have a couple amps but I didn't have this problem until I mounted the batteries from behind the front seats to the rear and ran the 2awg... I have checked all grounds, added additional, and one thing I notice is when I switch from isolated to open there is a difference in the flickering. Could it be the damn isolator switch itself?... any suggestions? Thanks much!