My R53 came with a Pioneer Premier DEH-P750MP head unit and some aftermarket speakers. The head unit has been perfectly functional with no issues while I've had the car these past 3 months. Today I was driving along with the unit off (though when it's off there is a clock in the center of the display that turns on), when suddenly the display turned white and the clock inverted to black. The right side of the screen turned blue because I think there are only blue pixels on that side. Then it went back to normal after about 10 seconds. Then it inverted again 5 seconds later and again 15 seconds later. It's completely random. As far as I can tell it's not linked to bumps, engine speed, current draw or anything else. It inverts every 3-20 seconds regardless of if the radio is on or off. Pressing any button on the unit when its inverted immediately brings it back to normal, but then it just inverts again 3-20 seconds later. The radio still works fine as do the other LEDs that come on when you turn the unit on. Its really got me stumped and it's a pretty annoying bug to have the thing suddenly blast white light from being totally black, especially at night. There is practically no technical literature or discussion of any kind about my particular unit on the internet. Help?

 

Check the wiring to see if the Illumination lead has been damaged or poorly modified. You may also have a fault with the HU itself.

 

I figured it out last night. It was actually just some Pioneer mode. I have no idea what caused it or why that's even a mode, but pressing the number 5 station button with the unit off is apparently what you do to fix it. Really strange.