Audio Systems: car radio problems, output impedance, pioneer radio

Question
I have just installed a pioneer radio into my car for the first couple of days every thing seemed to be working fine.  Now when i turn the radio on it will work for a minute then it will shut off then back on off again then back on.  It doesn't seem to stop.  It will do this weather I am playing a cd or just the radio I have adjusted the speaker controls from front to back side to side the problem doesn't seem to get any better what are some things that i can try to fix the problem before i just junk the radio and buy a new one.  The one I have was used before me.  
Thank you very much for your time,
Dustin

Answer
Dustin,
Here is a few things that you can check before giving up on this stereo. 1-If you have an ohm meter, disconnect the speaker/power connector from the stereo and check each speaker wire pair to make sure that none of the speaker wires are shorted to the vehicle's chassis or shorted together. 2-Double check that only one pair of speaker wires goes to each speaker, also check that none of the speaker feeds and returns are crossed. 3- check the ohms/impedance of each speaker to be sure that they match the required output impedance of the stereo.  Note, if connect your stereo to 4 ohm speakers and the output impedance of the stereo requires 8 ohms, you will be putting a heavy load on the output amps in the stereo and overheating/shut down and possible amp failure will result.

TOM,
T&D ELECTRONICS
[email protected]