Pioneer 2din HU suck Battery down.

I guessede right, my battery has been sucked up by the Pioneer radio during the last two weeks i wasn't using it.
My fault: i did not remove the fuse I put on the wire from the battery to the Headunit.
2 solution, removing the fuse each time i get out of the car at home or at work, or throwing this shit ion the garbage can and put the original GM headunit back where it belongs.

Why my HU draw so many power from the battery?

You must have hooked the 12v accessory wire for the radio up to constant 12v power.

That seems logicla but highly unpossible. The wires form the GMOS04 are well colored and it's impossible ot plug it the wrong way.
The only wire that does not ocme from the GMOS04 is the permanent 12V because the one provided by the GMOS never gave me anything but 5v.

Assuming you followed the instructions here: http://www.metraonline.com/files/products/INSTGMOS-04_web.pdf
It says in the instructions how to correctly wire your accessory through the 16 pin harness red wire and the 12v power to the yellow on your gmos04 harness...page 3.
Then I would say that the problem lies with your homemade "permanent" 12v.
You should not be using an extra wire hooked straight to the battery with an inline fuse. Thats your issue.

Get yourself a meter to test the wire is hooked up to accessory instead of constant power...sounds to me like you're wired to constant

Gotta find my own manual becuase i remember in mine they wrote i had to put together the two red wires coming from the metra harness and connect them to the permanent 12V of the Head unit.
I ran a wire from the battery because those two wires did give me 12V.
I have a multimeter I'll test that this saturday. Thanks.

mizzouguy said:

Assuming you followed the instructions here: http://www.metraonline.com/files/products/INSTGMOS-04_web.pdf
It says in the instructions how to correctly wire your accessory through the 16 pin harness red wire and the 12v power to the yellow on your gmos04 harness...page 3.
Then I would say that the problem lies with your homemade "permanent" 12v.
You should not be using an extra wire hooked straight to the battery with an inline fuse. Thats your issue.

Click to expand...

I found my leaflet i had with the GMOS. It's rev. 1/08/2014. The one you show me is from 2017, and there are some differences ! It seems they have improved their products over the years.

He wiring fort the radio is from here :
http://www.pioneerelectronics.com/StaticFiles/Manuals/Car/AVH-X2500BT_OwnersManual010213.pdf

2017 Axxess manual says : • Connect the Red wire to the accessory wire.
when 2014 says : • Connect the Red wireS to the ignition wire of the aftermarket radio.

This phrase is not clear to me. Does the ignition wire is the one that get 12v only when the key is turned on?

The english from the manual is not clear to me...

"From the 24-pin harness, connect the yellow wire to the radio's 12volt battery or memory wire." this yellow wire is printed constant 12v.
Page 46 of the radio manual it is shown the yellow wire needs to be connected to 12v constant supply terminal.
So I wired both yellow wires together.
Ground are always black so no issue there neither.

P12V is for Permanent 12V and I12V will be for Ignition 12V.


What I did wrong was to connect the ignition wire to the battery. Mizzouguy and YukonXL04 where correct.

Why did I do that, for god's sake?

Because last year when i installed it I found out that I was supposed to get I12V from the wires 1 & 4 (see picture below).
At least that's what is aked to do in my install leaflet.



It does not. Whatever position the key is in, I only got 4 Volts.

From here there are two paths to follow :

I buy another interface (not sure to buy another a Axxess interface), or I run a I12V wire from the factory harness to the radio.


Here's a picture of the sticker on my actual GMOS. Made in march 2015. Maybe a faulty run....

I just checked I bought it back in April 2015... too late for warranty.

Honestly I haven't messed with those modules much. 90% of the time I just run a acc12v to the fuse box and do away with all the chimes.

But I'm glad you figured out the problem

It's stuff like this that makes me happy I got my '00 Yukon XL...
Seems like it has the best of the old tech from the OBS, and none of the stupid stuff they put in for the '03+.