Need HELP! Headunit wont play while engine is running

**tjmike** · 02-04-2008, 07:26 AM

Ok here is one for the experts, i have a 2006 joyner sandviper / Dune buggy 3cylinder engine full size alternator 12v system. I recently installed a JVC headunit and some speakers. The headunit plays fine and everything works perfectly...with the engine off

when i start the engine the unit display just blinks, i have the constant power right to the battery, and the other 12v to a key on power, unit is grounded to frame. now i belive i figured out that not running the battery voltage is 12.25 running it is 14.40. so that trips up the head unit... question is how do i regulate the voltage to stay in the 12v range so the headunit will play with the engine running?

THANKS IN ADVANCE

**scott_fx** · 02-04-2008, 10:15 AM

all car audio is designed to run at 14.4v. thats not your problem

**tjmike** · 02-05-2008, 06:45 AM

well ok i understand they can run at 14.4 but there must be some voltage spikes coming from the alt. cause everything else is setup perfectly/ any way how can i regulate the voltage anyway?? I bought a Radio shack 7812 regualtor 1 Amp. i put it in line with the constant power, makes it light up but no play??

**DarquePervert** · 02-05-2008, 10:34 AM

Something is not wired correctly, plain and simple.

**scott_fx** · 02-05-2008, 12:20 PM

yeah, i have a feeling it doesn't have anything to do with the radio either. did you test all the voltages after you start the car? does the h/u stay on if you temporarily connect the ign lead on the harness to the 12v constant?