I'm not sure if this is the same but the ground wire going to the stereo is not really ground! Try running the hot wires for your new stereo right to the fuse box or straight to the bat and see if that cures it. I had a problem that was very similar but it wasn't a Tacoma.
I suspect the switch is bad.
How do I change the dimmer switch on my 1993 corvette?
help mower!
how to change dimmer switch on 1997 Honda accord
Use a dimmer switch or even easier squint your eyes.
a dimmer
A beam of light becoming dimmer is a physical change since it is reversible. Recharging its source will make the light beam bright again.
Usually a switch will only let you choose between ON and OFF, but a dimmer switch will let you change between Brighter or Darker.
A "dimmer" switch will change the brightness of lights.
You just need to change the bulb!
It's called a dimmer.
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