stock stereo speaker fader/balance problem

[ChewysT4R]

hey guys, I have owned my 07 4 runner sport for like 3 months now and just yesterday i started to play around with my stock ( without JBL) radios audio controls. what i notice when try to balance the sound to the rear speakers i have no change in audio, but when I balance all the way to the fronts my audio cuts out from all speakers. also when i fade to the right speakers the audio come out from the rear two and vise versa. anyone have this problem or now what is causing it. thanks in advance..

 

[DMX512]

I would venture to guess that the PO had an aftermarket HU in there and re-installed the OEM HU (incorrectly) prior to selling it.

 

[Anonymous4Runner]

I would venture to guess that the PO had an aftermarket HU in there and re-installed the OEM HU (incorrectly) prior to selling it.

He is correct - I would take it to a local audio shop for troubleshooting if you do not know how to troubleshoot/install the unit yourself. If any, they'd charge minimum labor for troubleshooting since it's a factory unit and not aftermarket.