The other day I was walking the dog and passed by my car that had been parked for about a week because of the horrible rain and road stuff. And I heard the radio on.
I got in and turned the radio off (which may or may not have been on for a week straight) and checked to see if the car still started and it did, but the radio didn't come on.

I have a Blaupunkt Los Angeles MP74. It has one wire that I connected straight to the battery for the constant power line which allows me to turn on the radio without the key in. I also have the standard 12V line that comes on when the key is turned to acc.

I checked the power and resistance of the +12 and Ground wires that work on the Acc. circuit, and they tested fine. It gets 12V when the key is switched and the ground is good.
I checked the inline fuse, and the fuse in the back of the head unit itself. It does not come on when the key is switched, only when I turn it on manually. It also needs to be turned off manually.

Anyone have any ideas?
Thanks!

 

1 bump. Because I can.

 

As I understand how that radio works, you should not be able to turn on the radio with no key. The Constant Power line is just to maintain the presets and clock, not to run the radio. If you hooked up a wire from the battery to the Acc connection, in addition to the wire from the Acc circuit, the radio should stay on all the time, once its turned on. Is there a separate amp being used with the radio? How is it powered up, if so?

 

It worked fine for four years the way I have it now. I'm pretty sure the manual said that the constant power can be used to turn on the radio with no key, but I will try to find it and check.
There is no amp. I have a simple head unit and 4 speaker setup.

Oh, also... the presets are saved without the radio being connected to anything, but the clock isn't.

 

my radio also works key or not, i kind of prefer that...

 

Do late models have a "radio relay" like early's? I would assume so. If so, my '86's works as poorly as my '84's did.

Looks like yours can be operated with the key off; from the owner's manual:

 

If the radio relay were bad wouldn't it not switch the 12V on and off with the key. Checking the wires with my volt meter I could see that the 12V would switch on and off with the key.
I have a feeling it is something internal with the radio sadly...

 

Yeah, I think you may be right, but it sould be worse. You just need to manually turn it on, right?

 

Yeah that's all. Not the biggest deal.

 

Today it worked. I didn't do anything to it, just switched on and off with the key just fine. Odd, but oh well. lol