So didn't know if this has already been posted but some may know already but I just serendipitously found this out when I was taking my navi drive out of the trunk to work on it (since my navi seems to be broke, so screen is all black and stuck on the "Please check your disc" all the time)

Stay up late. Go out to the car and disconnect the battery at 12am, then reconnect it. (or basically you just need to reconnect the battery/electrical system at 12am, it can be disconnected whenever)

Voila, clock is automatically reset to 12:00 and you're good to go!

I was working on my car real late at night and just luck would have it I was putting my navi drive back in and put the negative terminal back on the battery right around 12am by luck and the next day I was looking and saw the clock was the exactly right time and shocked and realized what I had done.

So hopefully this helps the poor TL owners out there with the broken navi screens!

 

I think reconnecting the battery at noon, when most of us wake up from our hangovers, would work the same way.