Yesterday I decided to hard wire my navigation (TomTom) and radar detector to the map light. There are some copper contacts in there that all carry 12V continuous. No problem for the radar, but when I connect my TomTom, it makes the backlight behind the buttons and the radio turn on. My TomTom has a 12V smart adaptor cable with some circuitry that is no doubt causing the problem. I suppose I'll let it ride and see if it causes any problems long term, but I don't think it will. I just unplug it when not in use so I won't run down the battery.

Anybody else experience this?

 

Sounds luiek u might be using a 12v constant that cant handle everything your throwing it.... or you might be arching a connection.... The radio also might turn on because the tom tom sends a pulse through its adapter but i doubt that....

I would make a new 12v source for anyhting you want to add liek that or use the ignition harness with the thicker gauge wire that can hedle all the accesories.