Wow, thanks guys, you've throw handbags and everything into the ring. I'm flattered. But now chill!
My problem is exactly the same described by the guy in this thread:
http://986forum.com/forums/general-discussions/31114-boxster-986-1998-radio-cutting-out.html
I am still convinced its an over voltage issue. Exactly as this guy describes, it works fine with the engine off at 12.8v but with the engine on at 14.4v it does not. Then also as he describes it starts working once its warm. We all know that as alternators get warm they become slightly less efficient, and hence the radio begins to work again. Also if the radio is cut out and I add a load to the electrical circuit, like turn the lights on or the window demister then the radio starts working again.
So now we're established its an over voltage issue let me rather ask:
What voltage does your 986 2.5 run at?
Threaded Mode
