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Radio stuff is a little tricky to diag remotely, but let's give it a shot. Check these two fuses first and we'll go from there:
AMP- under dash panel
RAD No 2- under dash panel
If your vehicle doesn't have an external amplifier then the AMP fuse will not be present so you should check the RAD No 1 fuse.
Forgive me if this seems a little basic, but the mute setting isn't on right?
You will have to look in the owner's manual for instructions on how to check that. They don't publish it in the repair manuals.
Did you find an AMP fuse?
If it has an amplifier it will have an AMP fuse. If it doesn't have an amplifier, then it eliminates a number of circuits to check for a fault. Not all siennas are equipped with an external amplifier.
It's not the mute setting. I just found a copy of the stereo manual for the sierra on line and if you adjust the volume up or down it cancels the mute.
I suspect that your model does have an AMP. According to the wiring diagrams from toyota if it doesn't have an external AMP, and there is no sound from the speakers, then the only possible cause would be an internal short inside the radio. Unless the detailers got the radio really wet, I can't see that happening as a result of the detail.
That might be bad news. There is really nothing between the speakers and the radio (according to the diagram) that could be checked to restore the sound. It's all internal.
I need to call it a night. I'll check back in with you in the AM to see if you have more concerns. I think you might be at the point where you will need to have the radio replaced.
One more thing you could try is to hard reboot the radio- Pull all of the radio related fuses for at least 30-60 minutes. Then reinstall them and see if it comes back to life.
If that doesn't work then you could try to reset all of the vehicle's modules by pulling both battery cables then touching and holding them together for about 1 minute. This will reboot every module on the vehicle. It's a last effort, but it might get it to work again and it's worth a try since it doesn't cost anything.
Any luck attempting to reset/reboot the radio?
I just wanted to check and see whether you needed any additional help on this one.
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