Hey guys, I just installed a JVC KD-R300 head unit into my 1989 Honda Prelude Si. It worked great for the first few days, but now it's acting weird. It works fine when I have the key in, but once I turn on the engine the head unit turns off and stops working. It works fine again once I shut off the car.

I have it hooked up through a wiring harness adapter, and all the wires seem to be crimped and taped correctly. I don't have any other audio equipment installed other than the head unit, and the car's wiring is still stock. Does anyone have any idea why this is happening, and how can I fix it? Thanks in advance!

 

first thing you need to do is grab a voltmeter and check the voltage on your red 12v switched wire and the yellow constant wire. both should read 12 or there abouts when the car is running. If you are seeing 0 on either wire then the easiest way to fix it would be to get power from the ignition harness and run the neccessary wire to the radio. If both wires still read 12v when the car is running then the radio is bad but I doubt that will be the problem. also check the ground making sure it reads 0v

 

ditto

 

not saying that this is or isn't it, but my friend's kicker amp wouldn't turn on when his car was on... turned out it kept going into protect mode because his alternator was putting out 16 almost 17volts instead of 14

 

Ditto the above^^^, it is the first thing I would check.

So I understand... when ign. switch is in the acc. position the radio works, when car is started it does not work, is that correct?
Question... does the HU still work if you turn the ign. switch from acc. to run, [ign. on but engine not running]? 94