pioneer headunit not powering on

[mangstyle]

Hello everyone, first I'd just like to start off by saying that this site is awesome! I've learned so much about my car from all the advice that's been given out on this site previously. I hope you guys can help me figure this one out.

Ok, so to start from the beginning, My stock Eurovox stereo stopped working a while back. I checked the fuses, the radio fuse was blown, so i replaced it, but it blew again. I checked the voltage coming from the wires and the constant and acc wires seem to be working fine. Two of the speakers seemed to be gone too, but they had given up a while before the stereo stopped working and sound came out fine from the other speakers. So i suspected that the stereo itself had a problem.

Luckily for me, i had a spare pioneer stereo lying around at home that was given to me as a present a few years ago that i hadn't touched. It was still new and in its packaging. I hooked it up to my car using a aerpro wiring harness, and grounded it to the factory earth point.

Problem is, its not turning on at all. I checked the wires again, and power seems to be coming through fine from both constant and acc, but no lights on in the unit. No fuses were blown in either the headunit, or the fusebox under the steering wheel.

My question is, could the fact that the speakers are shorted somewhere stop the stereo from receiving power? Is there some way I can definitively check if the unit works or not? What should i try next?

Your feedback is much appreciated.

[StoneX]

Shorted speakers can kill the internal amp which can cause the unit not to turn on.

The best thing for you to do is to take the Pioneer head unit out and wire it direct to a 12v source, either a supply or 12v battery. Just join the red & yellow wires to positive and black to negative and see if it turns on. If it does, then you need to connect a speaker and make sure it has sound and still turns on. If this is all good out of the car, then you need to start put it in the car but have no speakers connected to the look. If it works, you know it's the speaker wiring, if it doesn't you know it's the power or ground wiring.

Good luck

[mangstyle]

ahh i see. that seems like a good idea to try. cheers mate!

[vl_nick]

if the speakers are shorting out it can blow the mosfets in the unit, but it will still switch on just no sound. there is a fuse in the rear of the unit where the harness plugs in, check that too.
check the red and yellow wires right at the headunit plug to make sure there is power there and check the earth is connected to a solid connection. otherwise if all that is good i would say the unit is faulty.

[mangstyle]

thanks for the reply vl_nick.

The fuse in the headunit is fine, and I've checked the power in the red and yellow wires. They seem to deliver about 12.4V before starting the car, 14.4V after starting the car. A quick search through these forums tells me these are normal, so i assume the connections are ok. I hope the unit isn't faulty, but it was brand new when I took it out! albeit sitting around on my shelf for 4 years. Its a Pioneer DEH-3850MP I don't suppose anyone knows if there were issues with this unit?

I think StoneX's idea of connecting it directly to the battery, to check if it powers on is a good start to knowing if the unit is faulty or not. Hopefully I'll have some good news tomorrow, fingers crossed...

Thanks for the replies guys!

[madnuts]

ive found with the aeropro wiring harness the they have a few of the wires around the wrong way just check them to make sure

[mangstyle]

@madnuts
yeh that was something I thought could be the problem. I compared the location of all the wires on the factory loom to the aerpro harness. It all looked to be correct. Only thing was the harness didn't have an earth wire, so I just connected the ground from the headunit straight to a bolt on the chassis.

Perhaps it could also be that the wiring loom supplied by pioneer in the packaging is wrong? Probably very unlikely I suppose...

[madnuts]

where are u from

[StoneX]

I have a VT Berlina and the Aerpro wiring has worked perfectly for 8 years, no wires are wrong, even the earth was in the stock loom.

When you're measuring the voltage in the stock loom, where are you holing the negative probe? On the earth wire or somewhere else on the chassis? You need to measure from earth wire to battery/accessory wires to make sure the 12v is there, not just from chassis to those wires.

[madnuts]

i got a aerpro wiring harness the other day and the wires were wrong had to switch the powers around

[mangstyle]

@madnuts
I'm from sydney. However I believe the powers were the right way around. 1st, 2nd, pins were constant, AC, respectively on both.

@StoneX
Yep I've got the earth connected to chassis, but I'm measuring from the earthed wire.

[StoneX]

i got a aerpro wiring harness the other day and the wires were wrong had to switch the powers around

When you say that you need to say what model car it's for... I'm pretty sure you're talking about a VY/VZ Aerpro loom, not the VT one we're talking about.

[mangstyle]

Aha! Got it working! Turns out that I had everything wired up fine. But I needed to turn the key to the ON position to get anything working. I assumed that a clock or some indication of power would come out once I had it connected...how embarrassing haha

Thanks guys for your help though. Much appreciated!