ok the alternator went out on my car, and i replaced it with a weaker one till i get the money to buy one but this is not the question. here it goes before i replaced my alternator the radio worked fine, it is a jvc by the way and a equalizer running with it. but after i put the new alternator on it turns on sometimes but most of the time it just blinks like it is turning on and off. i checked all of the wiring and changed where i plug it into the fuse box. still does it. also it seems like when i hit a pothole it will somehow come on. if you need more info tell me i would be more than happy to give it to you

 

Check the wiring for the correct voltage, make sure there's not a speaker wire short somewhere (+ wire grounding to something). If the voltage is good & speaker wiring is good, it might be a problem with the deck itself.

 

your wiring is grounding out some where. I used to own an 89 toyota celica and had a problem similar to this. If i was driving at night (with headlights on of course) and I hit a pothole my passanger side light would go dim or vise versa (if it was dim it would go bright). One day I ripped out all the headlight housing on the passenger side. I found one of the wires had been cut and twisted together (yeah someone just got the two wire ends and twisted them like the twist ties on bread bags). There was residue from tape (long gone) on the wire ends. It seems when I would hit bumps the wires would either ground out or un-ground themselves. I pushed the wires down onto the frame with a pen, and guess what I got a dim light. I cut the wires back about an inch on each end. I put some heatshrink on the longer wire and pushed it back so it wouldnt shrink when I soldered the wires. i soldered them, shrunk the heat shrink over the solder, and still wrapped it in electrical tape. The problem went away, until some kid decided he didnt want to give me the right of way ( i had the right of way) and I side swiped him. His insurance paid for my car and so on blah blah blah. The point is your grounding out somewhere.