prodo63

I've got a very strange issue on my hands with my aftermarket head unit. I purchased this Pioneer DEN-P3900-MP head unit in the summer of 2007. I installed it myself using a Metra wiring harness and had absolutely no issues with it until last week. Randomly while driving one night, my entire stereo lost power. I was not playing anything loud at the time, just listening at a normal volume. Strangely, I was able to power the unit back on after a few minutes. Then, the next afternoon while driving home from work, I had the same issue and could not get the unit to turn on again.

So I pulled every fuse related to the stereo and replaced them. I bought a new fuse tap connector for my accessory wire and have it running with the windshield wiper circuit. I was able to get things working again, but now twice in the past 5 days after having everything working fine, I have had the same issue occur. Yesterday, I drove home from work with everything working properly, and yet somehow this morning when I left, the stereo was DOA from the moment I turned the key.

Here is what I have tried. I pulled the head unit and took it to my local BestBuy to have them do a tabletop test. The head unit appears to be fine (and as I said it did work properly in the last week). I changed the 15 amp fuse in slot 23 that is labeled as being for the radio. I also changed the 10 amp fuse that I am using in my dual slot fuse tap. I have ensured that I have live, uncompromised fuses in each slot.

What am I missing? I have noticed that I have very poor speaker performance lately. It seems as if I need to tune my head unit to much higher volume levels to achieve a normal listening volume. I also hear a strange sound from my right front speaker (almost like I'm listening to it from under water). Is it possible that a speaker ground might have came loose and is causing a short throughout the entire system?

I guess I am trying to determine what I might be overlooking, because right now I see no explanation for why I am able to get this to work and then it fails again for apparently no reason.

I should clarify, I am not simply blowing fuses and then replacing them to get it to work. In fact, I have not had one fuse yet appear to be completely burned and broken at the junction point. I have noticed that some of them are 'dead', but not fully broken which makes me wonder what is going on. Also, even when I place brand new fuses in the appropriate slots, I am not able to get the stereo to work predictably. I tried that tonight and was unable to get power to the unit.

Am I missing something? Is there another fuse or relay I need to be concerned with that can help me in this situation? Thanks in advance.

EmperorJJ1

iTrader: (5)

speaker is probably blown..

double check the impedance of your speakers first. do u have the pioneer system or no?

prodo63

No, I have the basic stock sound system. I should have mentioned my vehicle is a base model 2006 LS Coupe.

When I upgraded the head unit, that was the only thing I did. I never replaced any of the speakers. How would I go about determining if that is my problem, and is it possible for a speaker to produce this effect on my head unit?

EmperorJJ1

iTrader: (5)

yes if a speaker is blown and the impedance is dropping it will heat up the HU and do exactly what ur experiencing... once it cools down for a bit it will turn back on. Trust me man check your speakers probably that right front speaker. check it all asap before you do some sort of damage to the internal amp on the HU

prodo63

Ok this situation just became even more confusing.

Saturday, I pulled off the door panels, disconnected every speaker and tried to turn on the unit. No power. Nothing worked. I was messing around a little bit with the harness and somehow it was able to come on, and then usually it would turn back off while I was holding the head unit in my hands and moving it around.

So, my solution was to simply try to re-splice the main battery terminal power line (yellow cable). I did that, it worked instantly and I put the system through its paces. I cranked it up as loud as it could, tried to get it to heat up and blow a circuit but it did not. I figured, problem solved.

This morning, I went to work, all was well. Then in the afternoon, I go to head home from work, turn the key and everything comes on, go to change the station and boom, failure. This time, it seemed more like a blown fuse because my windshield wipers were out as well and they are sharing the same circuit with my fuse tap.

So at this point, I am highly irritated and I decided that I would try to replace the fuses when I went outside after dinner. I go to turn the key, and as if by magic, the head unit comes right back on, no loss of memory even. All of my presets and my settings were maintained as if it had never lost power.

What gives here? I haven't been able to isolate the issue. It does not appear to be a fuse problem because today looked clearly like a blown fuse scenario, and yet it magically works a little bit later without ever changing a fuse and no visible damage to any of the affected circuits. It doesn't appear to be a speaker issue because even with no speakers wired in, the head unit did not come on on Saturday. It doesn't appear to be related to heat because I had the unit fail to turn on after sitting in my cool garage overnight, and also had it fail when I got into the car after a relatively overcast day outside.

I guess at this point the next thing I want to suspect is the wiring harness. Is it possible for something to have gone awry? Beyond that, the only other options are the head unit itself, which it seems odd that it would be this sporadic, or some kind of wiring issue with the car itself. I have heard that in some models, when the battery is dying, the radio and other accessory circuits will be disabled. Would that be a possibility in my '06 LS?

The bottom line for me is that I am taking a vacation in two weeks and making a 12 hour drive each way. The last thing I want is for some kind of catastrophic electrical short that affects more than just my radio, and if I had to deal with a silent car for 12 hours I might not make it back in one piece. Is there anything I can do without wasting money to buy a new head unit? I don't feel like that would be a smart move considering what I have already seen.