MRubenzahl

1999 RX 300 with the factory radio/CD has no sound. Display works fine, shows AM, FM, CD, etc and CD time display is ticking. But no sound except for an occasional bit of sound for less than a second.

Important clue: Turn off the car and set the ignition key to the ACC (accessory) position and the radio plays normally.

Bad ignition switch? Bad wiring? Anyone have any recommendations? I imagine that gettting into the area behind the ignition switch is not fun...

Ratchey

The issue is most likely the remote turn on for your amp. If it were the ignition switch, I doubt the head unit would even power up.
Test the wire to see if there is power when ignition is on and in acc position. It may be easier to cut the wire at the amp and run a new one to an switched fuse if that is the issue.

MRubenzahl

Ah, interesting idea. I am not familiar with the layout of these components. I think I read that the amp is behind the rear seats? Is there a diagram or description somewhere that shows these? In particular, what wire do you mean -- something that goes from the head unit to the amp?

Ratchey

Not sure where it is. There may be wiring diagrams floating around. If not, you can buy them from https://techinfo.toyota.com
There will be 2 harnesses going into the amp. A small one which carries the signal from the head unit and a large one that has the power and speaker outputs. The wire will be in the large one. The wiring diagram will tell you which color and which pin on the harness it will be.

MRubenzahl

Do you know where the amp is, physically and how to get to it?

Ratchey

In my rx450h it was in the rear, under the deck on the left under a plastic cover. Not sure where yours is.