Navagation display not coming on, black screen.
checked ign power and unswitched power to dispay and dvd unit in trunk.
both had 12 volts on wh/red &yel/red wires . Which unit do I need to take out?

 

Here is a more detail on my previous post on the Sunday, on the black screen issue. On the display , all the non screen controls are working, radio, CD, temp controls etc. Like I said earlier, I have ign voltage and battery voltage on display and cd player in trunk.
Here are a few things I have tried. I've cleaned org. Disk and ejected its and reloaded it several times. I have disconnected battery for a few hours to reset every thing. I noticed you can't hear the unit in trunk doing anything when I load disk and shut the door. I would think you should be able to hear something. The only other thing I havn't done is clean the laser eye in the dvd unit. Is there any thing else I can try?

 

You should run the system diagnostics and see if it comes up with an error code which you can then further investigate.