Why do my accessories cycle on and off?

Very weird problem. Factory stereo, 1991 Toyota MR2.

Started yesterday with no recent changes. I turn the car off, the radio stays on! The clock also lights with the accessories, so I can watch it to see what's going on.

If I sit for a minute, the clock fades, then the radio finally turns off, then the clock finally goes dark, but this is where it gets weird. The instant the clock goes dark, it immediately gets bright again and the radio comes back on. I'm a fair mechanic, but I don't even know where to start. I guess I'll unplug the radio and see what happens.


land cycling