wa8yxm wrote:
If you do not have LED lighting (As someone up-thread said LEDs can cause radio interference) hang a digital volt meter on the radio's power lead within six inches of the radio if you can (IF there is an inline fuse you can tap in there and not have to cut or pierce wire A single strand of stranded wire is enough to feed the meter)
I'm suspecting voltage loss
LED interference ususally comes in as NOISE.. not volume loss. Though some of my radios might present as volume loss. but they have industrial strength noise limiter circuits which are not normally present in car radios today.
Thanks for another potential cause, other than LED. I have a spare AGM battery and may use it as a power source for a few day's to isolate the radio from the normal power source to see if the volume loss shows up.