[Boatanchors] Weird service problem

[WØQFC]

My first thought is that you are connecting it wrong.
The connection to the speakers have nothing to do with the 12vdc input.
However, some of the older radios had some really weird connection schemes 
and you must make sure they are correct.
I have a bunch of car radio schematics and if you give me the make and model 
number of the radio, I will look see if I have a schematic.
If that does not work out, then try some of the automotive parts houses ~ 
they sometimes have universal connectors for various brands of radios for 
GM, Chrysler, Ford, etc.
Good luck!

73,

You said "speakers" so is it a stereo radio?
Gene, WØQFC (OK on QRZ)
Spring Hill, Florida 34606
WEB SITE:
http://www.w0qfc.com