Originally Posted by _fng_
PP was set up to tach originally but voltage dropped too much (1.5v) with key on, PP customer service recommended rewiring purple wire from tach to ignition switch and run another ground wire directly from negative battery terminal.
No, I'm not manually controlling the banks. The perko switch that I have has only "on" and "off" not like the 1/2/off I've seen. Since, I do not manually switch from battery 1 or 2 then a 16awg to ignition switch is next move? I can do that!
Correct. So now make sure you wire the ignition switch properly. I was a bit baffled but It's clear now..
Purple should go to accessory, causing the isolator to fail open when you switch there.