Pioneer Nav system installed

[Klaus]

Tucson,

Like I said, I don't have access to the installation instructions for your stereo, but the aftermarket stereos I have installed usually have a wire that should be connected to the dash illumination circuit. Therefore, when the radio senses voltage on the illumination circuit, it assumes that it needs to change from day to night mode. When you are switching your radio to "night-time mode", you are telling your radio to dim when it senses voltage on the illumination circuit. When you turn the mode off, you are telling your radio to ignore the illumination circuit, and your radio will not "dim" to black.

If your dash lights are always on, day or night, then that problem will need to be fixed. Otherwise, the radio will always think it is night time, because the illumination circuit is always energized. Again, IF your dash lights are always on, day or night, you have some other problem (could be the DRL mod - remove the jumper and check to see if the lights are working correctly).

If your dash lights are working normally (off in daylight, on at night) then the wiring on the radio itself needs to be connected properly.

The more I think about it, the more I think your DRL mod is causing the problem.