My clock has been dimming randomly for the last couple of months. Headlights on or off it doesnt make a difference. If i push in on the clock it brightens up again for a little and then dims again. A few days ago the clock did not light up at all but then came back a few hours later. I saw a similar problem in the 3rd gen forum but the light did not come at all.

 

This is a sign that your clock is going to die soon. This happened to me in my '95. Luckily, I found one at a local junkyard for $20.00. Nissan wants $200.00 for this part!