LOUD RADIO NOISE AT STARTUP

That's quite interesting sounds like some sort of a short or something along those lines the plug flopping not completely connected I have no idea. I generally never have the fan or the radio on when I unready or shut the car off I've just been that way since the '50s I don't shut my car off with the fan running full blast the air conditioning compressor blue light on or the radio at full tilt like in an airplane or serious vehicle switches are turned off when the vehicle is shut down in proper sequence I can't help it. That alone in itself helps save myself from a lot of these issues. It doesn't even sound right taking power away from an air conditioner a full tilt running stereo even a blower motor I don't do that at home either My power things down then take turn the breaker off service the equipment and bring the power back up properly not just flip the breaker with everything set to full tilt but that's a personal thing has no bearing probably to anybody else.. but it sounds like dirty signals of some sort

 

Is it the standard radio or the jbl upgraded model on the higher spec 07 ?

 

Back in the old days this is when granddad would have the electric contact cleaner out and knobs off trying to clean what used to be your volume knob plates or whatever was in there that when you turn them they could get noisy Make a squelching sound or whatever that noise is etc I don't think today's modern electronics generally have these problems and if they do I don't think you could easily replace just the volume knob and circuitry in this type of solid state setup or it wouldn't be worth your time in such a Not new vehicle with radios being plentiful out in the wild factory nice ones some people never turn these things on That's the nice thing about parts on a Prius especially an old generation 2 04-9 is lots of older folks bought these cars who may have never turned the radio on NPR or not. So many of the Gen 2's I pick up the radio's been turned on two or three times by the grandkids when they took him to the store other than that the car sat in the garage went to doctor's appointments and to the grocery store a couple times a week and 17 years later only has 64,000 mi on it because well it's taken care of and used like it's needed and usually these cars will be slowly halfway dead all the time because they're not being driven as soon as I come along and buy it and start driving it everyday batteries come back up things start working again maybe for a year almost two and then we're doing things

 

Just a guess. Do you think its holding some sort of residual charge that builds up overnight?
i would suggest checking the earthing

 

it's really a sign of dying radio, one or several of the capacitor failed and discharged overnight. You could try experiment how long it takes to act up (like start it again every 4hrs or 8hrs) Luckily you could buy the radio for this in ebay really cheap or just go aftermarket.

 

I have an '05 with a Clarion in it that I've never really liked and the little trim piece that goes under the stereo doesn't fit well and it's kind of bowed I've tried to fix it with a heat gun and various and sundry things but it doesn't do right You have to really look at it to tell I think the Clarion has some form a GPS in it and what have you I can't remember It fills the space nicely but it's missing some of the things I believe I never used it the remote sitting in the little tray underneath it and it's still in the car if anybody would like it I believe it's in perfect condition nothing wrong with it it's wired and correctly so that every time you turn the car on the Clarion welcome screen comes on like when you first bought it so somebody wired it so that when you turn it off it doesn't hold its memory it starts up like a brand new machine like it just came out of the box but that was just an installer's fault there's nothing wrong with the radio and I think it's a CD player and what have you It was a three or $400 affair when it was purchased I believe

 

While that's not a bad idea, how about this for a wild guess:
Can't see for sure but it looks like there is a CD player with the radio.

It might be "testing" the CD player to see if anything is loaded by running the motor.
If it hasn't been used much or at all in 10 years or so, it might just be "stiff" components in there.
If the drive system includes any rubber belts, they probably are shot by now.

I would suggest that you put a CD in the drive to test it........but you might never see that CD again.

 

Just take the radio CD player WMA thing out of an '09 and pretty much be done with it I have a Clarion that's in a '05 right now that works well You can have it if you want it The car may go to junk with it still installed.