pioneer deh 400ub wont power off

I bought the unit about a year ago and installed it just fine. I tried to change the time on it, due to Daylight Savings time last week and the unit wont power off. According to the manual, you hold the Source button down until the unit powers off and the clock appears on the display. When I hold the Source button it cycles from IPOD to Tuner, etc. Never powers off. I have it installed in a 03 Ford Taurus. the only thing that I noticed (dont know if it is relevent or not) but sometimes if I have the source on Tuner and turn the car off. the next time I turn the vehicle on, it automatically turns to the IPOD source. Everything on the unit works fine other than that. Can anyone offer any ideas?

I figured it out. I had to remove the fuse as well as unplugging the unit. huh... does the fuse keep some sort of power to the unit even though it's not powered on?

Yes. The red wire is a constant, or "memory" 12V, so apparently all the deck needed was a reset, accomplished by removing all the fuses.It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

Not that i'm arguing but the pioneers i'm accustomed to, the yellow is constant and the red accesory! Is it different in the U.S?

Yellow is constant.   And if it is a real OLD Pioneer Orange is constant and yellow is illumination.

Just checking!