I own an '01 TL w/nav with about 150,000 miles on it. I have an intermittent electrical problem. Sometimes the lights on the center console [nav, stereo, climate control] will flick off for just a second. Nav. goes out, stereo flicks off, if I'm running heter or defroster, it has a quick power hit too. Sometimes this will cause my headlights to go out. When the headlights go out, I pull over, flick the headlight control on the stalk, and they come back on. My mechanic replaced the ignition switch about a month ago, the problem stopped, then re-occured last week. Any ideas? Can the dealer easily diagose?

 

I would inspect the headlight/turn signal switch assembly behind the steering wheel.
That will tweak all your lights, and if its causing a short- could affect other electrical on the same power circuit,
I had 2 wear out on a maxima, the replacement lasted 1 day beyond its 1 year warranty.
Look under the hood at the fuses for headlights and make sure they are all tight and ok

 

^ That or a multiplex