2004 infiniti g35 with metra 70-7551 harness issue

[cash94 10+ year member]

I have a 2004 infiniti g35 that I installed a alpine head unit in with a metra 70-7551 wiring harness. It has a bose system. I wired the head unit harness to metra harness color for color, straight forward. I plugged in the metra harness to stock harness, plugged in the head unit, hooked up the metra harness rca's to head unit. Head unit wouldn't turn on. took a meter and looked to see if I was getting 12v on the harness between yellow and black wires. nothing. so, i matched up the metra harness yellow and black wire to the stock wires and the yellow leads to the cars yellow wire and the black wire leads to a gray wire on the stock harness. I tested for 12v there and still nothing. I tested stock harness yellow to body ground and got 12v. so the metra harness ground doesn't connect to the correct wire. so I made my own body ground and the radio works now, but the speakers arnt producing high volume. the stock head unit was louder then what the alpine is producing. any help? thanks in advance

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[Jepalan]

Which Alpine head unit?

How much softer is the volume now? A *little* quieter, or barely hear it with HU volume cranked?

 

[Jepalan]

Which Alpine head unit?

How much softer is the volume now? A *little* quieter, or barely hear it with HU volume cranked?

 

[cash94 10+ year member]

its the alpine CDE-HD148BT. the volume is low enough where you can deff tell a difference from the stock hu. if you had both head units max volume the stock hu is deff louder, id have to guess the alpine is producing volume of give or take 50-75% of the stock

 

[Jepalan]

The harness instructions recommend using a HU with "4v or higher pre-outs". Your Alpine has 2v pre-outs. That is why is sound 50% quieter. You will need a good line driver between your HU and the harness RCAs. Get a line driver with at least 4v output

You could also put a decent line-output converter on the Alpine speaker outputs - if you go this route, get one that will put out at least 4v on the RCAs.

 

[cash94 10+ year member]

the head unit has 4v preouts though, also somethings wacky with the settings, when I try turning up like bass or treble, each +1db it gets quieter.

 

[NFrazier 10+ year member]

1. Nissans don't have a chassis ground in the harness, you always have to create your own (even if the Metra harness is pinned for one, it doesn't matter) - some people use the antenna as a ground source for the radio, this is not recommended. The factory radio grounds through the metal brackets it attaches to which is attached underneath the radio and up underneath where the clock sits, to the car.

2. It is sometimes best to use the 70-7550 as the harness and forego using the 7551's rca connectors - usually using a radio with the 4v preouts is good with the 7551, but u may wanna just use the 7550 to see if that rectifies your issue - as the voltage in to the amp will be much greater.

if you need any help, give us a call/text/e-mail

7746435505 (call or text it will go to our e-mails)

sales@innovative-ca.com

http://www.facebook.com/icmass (can send us a message there as well)

 

[cash94 10+ year member]

Thanks for the info, I will try that and see what happens