stereo blinks off at startup

[96KITT]

This is my 2nd TA and has always done this. Whenever I start the car the radio will blink off for a half sec. When it's cold out (less than 50 degrees) the keyless remote won't work and I have to reprogram the keyfob. It's like the BCM doesn't have a constant supply of power to it. Brand new Optima battery - same problem. Where can I start to look. ALSO, I have a mp3 player installed and rigged up through the multi-disc changer control on the HU, and whenever power is cutoff to the radio (battery disconnected or really cold overnight) I have to futz with it in the back of the stereo until I can hear music coming through. The first car did this too. Any ideas??

[quicky06]

none of the electronics will work when the car is being started. it takes all the juice and gives it to the starter. every car i have driven does this

[02z28ls1]

This sounds more of a problem than that-it's losing power to the BCM and the mp3 when it gets cold out.You need to check battery voltage at that time to figure out what's going on.If battery voltage is good then there is a bad connection somewhere,probably battery terminals.They have to be clean and shiny and tight to pass electricity-I've seen a lot of people with corroded and loose terminals have weird problems like this.When it's cold out your battery loses power and exaggerates starting problems.If you can get the optima checked (autozone freebie)that would eliminate a freak bad optima as a cause-and that is a quality battery from my experience.