No power to head unit

[xJustin]

I'm upgrading the existing factory head unit in my 06 Nissan pathfinder. I found one of my old head units from a few years back (2005) when I upgraded my accord with a newer system. It is a pioneer deh-p4700mp.

I went to Walmart and bought a harness, wired everything up and plugged it into my vehicle's harness --- nothing, no power when acc or full ignition.

So I decided that there must have been something wrong with the head unit being the reason I replaced it in 05 so I removed the aftermarket harness and plugged in the factory head unit to the vehicle --- nothing. So I got worried I did something wrong, but when I sat the factory head unit on the mounts it started right up.

So I wondered if maybe it had to be grounded in the brackets to get power, I reconnected the pioneer and sat it in the bracket but still no power.

I'm extremely novice on car audio, I would greatttttly appreciate some insight from some of you more advanced guys.

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[skylineTT 10+ year member]

might have to run a different ground wire to the unit. My cherokee was like this.

 

[xJustin]

And a quick question, the aftermarket harness has an "amp ground" wire and 2 "chassis ground" wires.

I have the amp ground capped off since I have no amp

And the 2 chassis grounds spliced together.

Is this correct?

Edit*

I ran the ground from the head unit to the (-) terminal on the battery, still nothing.

 

[DukeNut 10+ year member]

Go to installdr

According to it:

Amp Ground Wire (connect this wire to the radios ground wire)

 

[NFrazier 10+ year member]

1. Nissans need a dedicated ground (those cars have a metal support beem that goes across the entire dash that you can ground the radio to).

2. Have you checked your fuses? Seems like a simple issue.

Here are the two radio fuses. The one in the car is typically for the accessory power while the one under the hood is typically for the radio's constant power.

10 AMP #4 PASSENGER SIDE DASH PANEL

20 AMP #29 PASSENGER SIDE UNDER HOOD

Physically inspect these fuses. Don't use a "fuse tester" as it can sometimes give false positives.

 

[xJustin]

The wife started yelling "are you ever going to be finished" earlier so I reinstalled the factory head unit and cut the splices off of the harnesses.

But now I'm tempted to give it another try tomorrow.

For the sake of argument, if it were one of the fuses wouldn't the factory head unit have problems as well?

And would grounding issues cause the aftermarket head unit to not function or light up at all?

Now if I were to do it again, I would splice the two "chassis grounds" together, then connect both "amp ground" and the ground wire from head unit to the metal bar behind the head unit you

mentioned.

Is that correct?

Thank you guys for responding so quickly.

 

[BratRod 10+ year member]

Some HUs are grounded through the antenna, some require their own wire. I always run another ground wire when installing any deck, regardless. Start with running a ground tomorrow

 

[Buck 5,000+ posts]

I don't think it would be a fuse if your factory radio worked, unless it was a fuse in the back of your aftermarket radio.

 

[NFrazier 10+ year member]

Some HUs are grounded through the antenna, some require their own wire. I always run another ground wire when installing any deck, regardless. Start with running a ground tomorrow

Any radio can technically ground through the antenna as the antenna is grounded to the chassis. The ground however is so far removed that it's not a good idea to ever use the antenna to ground the radio.

The wife started yelling "are you ever going to be finished" earlier so I reinstalled the factory head unit and cut the splices off of the harnesses.

But now I'm tempted to give it another try tomorrow.

For the sake of argument, if it were one of the fuses wouldn't the factory head unit have problems as well?

And would grounding issues cause the aftermarket head unit to not function or light up at all?

Now if I were to do it again, I would splice the two "chassis grounds" together, then connect both "amp ground" and the ground wire from head unit to the metal bar behind the head unit you

mentioned.

Is that correct?

Thank you guys for responding so quickly.

If it was a fuse issue than yes the factory radio would not work.

I personally would never use those y-harnesses from Wal-Mart. Go to a shop and grab the 70-7550, if you have bose attach that black/white and the radio's ground to the bar behind the radio.

Up to you. It's weird what you are experiencing with multiple radios yet the factory works perfectly fine.

 

[xJustin]

For clarification, I only have 2 head units.. Factory and the pioneer.

Where would the fuse be on the pioneer?

Also, I did not hook up the antenna when I was testing the aftermarket unit. I'm trying to be relatively cheap with this and was going to take it back in the event it would not work and get my $20 back.

Sadly I live a looong ways from any audio shops and Walmart is about my only option.

I'm about to go attempt this all again, completely reworking the harnesses and all.

 

[audiobaun 5,000+ posts]

Simple ,simple,quick test to check a radio for power..Take red/yellow(sometimes even orange if youd like)splice those together with about 1ft of wire/speaker wire,and take the radio to the car battery, and touch the pos post with the red/ect, and the black to the neg post..if she doesnt light up, more than likely it needs repair,Check to see if there is a 10amp fuse on the back of the radio also,may change that since its been sitting,may be the only issue

 

[xJustin]

View attachment 26540339View attachment 26540339

So I feel like a complete idiot. All I had to do was open my eyes apparently. I'm assuming the fuse slot with 10A printed next to it should in fact have a 10 amp fuse in it

 

[audiobaun 5,000+ posts]

View attachment 26540339View attachment 26540339

So I feel like a complete idiot. All I had to do was open my eyes apparently. I'm assuming the fuse slot with 10A printed next to it should in fact have a 10 amp fuse in it

Yes sir..Simplest of all things,can bring it all down..lol..Throw a fuse in there, and try her out.

 

[xJustin]

Ok I just threw in a 10 amp fuse, wired the red and yellow together, did the battery test and I got crackling + a lot of smoke from the head unit instantly. If it wasn't damaged before I imagine it is now. Probably not worth taking everything apart to reinstall at this point. I think I'm just gonna give up.

 

[audiobaun 5,000+ posts]

Ok I just threw in a 10 amp fuse, wired the red and yellow together, did the battery test and I got crackling + a lot of smoke from the head unit instantly. If it wasn't damaged before I imagine it is now. Probably not worth taking everything apart to reinstall at this point. I think I'm just gonna give up.

LOL..that hu was deff fried then from the beginning.I always test amps out and HU out from the batt, and never have had an issue, unless its bad as yours was..prob the reason why it was setting in the first place..