Originally Posted by supernukes
Ty for your response. I worked on system yesterday and after playing with all wiring (new harness from new BTA8100) I am convinced it is subwoofer preamp signal from deck. I will confirm today by using preamp signal from rear speakers (which I know to be working). BUT pls expain a bit more about checking ground. I have a meter from radio shack use ohm or dcvolt and where should I check... at connection site or in wire itself running to sub?
Set your DMM to measure resistance. Use one probe at the ring terminal of the ground wire and the other probe at the ground connection of the Tube (wiring harness). This should read zero, even when attempting to wiggle the ring terminal.