I've missed you guys....

I'm in the middle of installing a Sony headunit (CDX-GT640UI), and have an extra wire (see pic). Antenna? Amp?

I'm using the Metra 70-1786 harness. I do not have a CD changer.

I have sound, but it is SUPER quiet. I have to crank the sound to hear anything.

There are no inputs on the back of the head unit that will fit the wire.

Am I screwed? Help please? Thanks, Dustin

 

Antenna wire from the metra harness needs to go to amp turn on wire from your head unit. That is an extra antenna wire that you can't use with your head unit.

 

i have the blue/white of the Metra connected to the blue/white of the Sony. Both manufacturers say that is the "amp turn on" wire.

the solid blue is power antenna according to both. i am not using that wire on the Sony. The Metra doesnt even have a solid blue wire.

see anything wrong?

 

p.s. i just connected the black (ground) of the Sony to the black of the Metra. That shouldnt be an issue for the grounding, right?

 

In my experience it is never a good idea to trust aftermarket wiring harness diagrams. I would cross reference the acual rover wiring with the sony wiring and just consider the metra harnes to be an intermediary with little significance.... but thats just my 2c's

 

I see, yes I agree with the "odd" wire being an antenna and if you do not have one connected you will need an adapter for that. as for the blue/white amp turn on wire, follow it into the metra harness and make sure there is actually a wire on the rover side that it actually connects to. If there is not another wire there let me know what wires (by color) on the rover side do not have a connection on the metra side and we will find out which is the right one.

a couple of side notes: rule of thumb on factory ground being strong enough is its wire size (thickness or AWG) VS. the aftermarket grounds wire size, if it is less than half the thickness it should be replaced.
Many times the factory wiring will use the amp turn on to power the antenna as well (if it is even powered, ours aren't powered in the sense of motorized but I think they are amplified)

this may help you out, not sure which one is yours
http://carstereohelp.net/wireharness_LandRover1.htm
http://carstereohelp.net/wireharness_LandRover2.htm
http://carstereohelp.net/wireharness_LandRover3.htm
http://www.nexxia.co.uk/More_Information/ISO_wiring.htm

 

arent lots of people using the Metra 70-1786? you can see it here, it only has one blue wire, its blue/white: http://www.sonicelectronix.com/item_...mpaign=froogle

that blue/white wire is connected to number 5 on this A diagram (black/red wire), labeled "12v output power" : http://www.nexxia.co.uk/More_Information/ISO_wiring.htm

what could lead to low speaker volume? no amp power? how else can i check if the amp is gettting power?

chris, do you agree that the coaxial-looking wire does not need to be connected? i dont think im getting FM reception, but its hard to tell.

 

ok here are a few things to try, first turn the system on until you can hear sound (all the way up) then disconnect that blue/white wire, if this is wired correctly and the problem is somewhere else the sound will then go away, if this wire is wired to the wrong place (due to the Metra harness being pinned wrong) then there will be no change. Here is the thing, the Metra harness is kind of universal for most European vehicles however there are occasionally slight variations and this maybe one of them, it is often we see the power wires backwards on these harnesses and I think this issue may have come up once or twice before.

and no the coax wire should not be required for power if the unit is turning on then it is getting power, you should only need this if you are not getting reception.

 

good call! disconnected blue/white wires and nothing changed. so i guess no power is going through that wire and thus the amp is not powered, leading to quiet speakers.

so whats next? either (1) the Metra harness is wired wrong, and not sending the blue/white power to the correct vehicle wire or (2) the head unit is not powering that wire for some reason [i searched and searched for options on the head unit regarding external amp, but couldnt find any].

any other options/thoughts?

 

first off how many pins can there be in the big (I think yellow) plug? 10 or 20?
lets start here what wires (on which factory plug) are not connected to the factory radio? please give wire location and color, my guess would be it's one of these wires but don't just go plugging into them until we determine which one it is, A1 or C6 (if this does not go to audio signal wires),

use one of these pages to label each wire location depending on how many pin slots are on the biggest plug:
http://carstereohelp.net/wireharness_LandRover1.htm
http://www.nexxia.co.uk/More_Information/ISO_wiring.htm