I cannot find anything useful with a search so maybe you have some advice where to start.

I suddenly lost my dome light/map lights, door lights, 12v outlet and radio. Quick search found the interior lights C/B blown, after replacing, the interior/door lights still don't work, nor does the outlet. Here is where it gets strange...the radio will work when the Engine RPM's are above 500 (ie. when I am driving.) And it shuts off when 1. car is at a low idle 2. when you turn on either dome/map lights 3. when a door opens and 4. when you plug something into the 12v outlet. I am thinking a possible ground issue or power supply, but cannot find how those are wired together. I don't really have any idea where to start to look for a ground for them. Any advice? (1999 SH - no recent electrical work or aftermarket electronics)

 

This may or may not do anything, just check your battery for corrossion and tighten all the battery ground and power wires down.

 

Firstly, I'd check the charging system, and make sure that you're getting the 13.8V you should be at idle.

Otherwise, it sounds to me like you have a ground problem, insufficient ground will show when you start changing up load, like when you turn on/off lights, etc.