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Discussion Starter #1
Hi All, I love my GTV so much and take it everywhere far and wide so I thought I might now finally install some entertainment to keep me occupied for those rare moments int time when I'm sat in the car but not actually driving it somewhere.

I'm installing a in-dash multimedia unit (an old one my neighbour had in his garage and let me have). It has a complex wiring setup with all its other peripherals.

I'd like to learn and do it as I go along, Im a pretty savvy guy in most things (I hope:) and Im interested in Auto Technical areas and think it would be a useful skill to have considering how much I love cars in general. Anyway.

I cant find any wiring diagrams in the car manual etc and I dont have the Haynes.

I think I got most of it by deduction. But Id like some info on the wiring setup on the GTV as Id like the info before I go trial by error and potentially mess something up. One plug connection has 8 wires that cover all the speakers as standard, fine.

Now on the other plug connection. I've searched for the last 2 hours on and off this forum but I cant find the answer so no-one have a go..:) The sticky on aftermarket head unit wiring for 147, 156, and GT is super and I tried to apply it to mine but its obvious that there are quite many differences and I just dont want to jump in without checking with some wise souls here, some who must have done this before..

I've made some assumptions (which may be wrong) and have some clear gaps in what each wire is what.
I;ve assumed:
black = earth
yellow = battery
red = ignition?

But what about the other two? They are both striped:
red/green = ?
red/blue = ?

I've also got to make a connection to the parking brake (do to the safety mechanism on the unit stopping any viewing the screen while the car is moving), does anyone have any pointers on how I can easily find the parking brake wire. I'd love not to have to strip my dash apart if possible.

Thanks Everyone.
 

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AO Silver Member, 155 Lounge Winner 09
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I've made some assumptions (which may be wrong) and have some clear gaps in what each wire is what.
I;ve assumed:
black = earth
yellow = battery
red = ignition?

But what about the other two? They are both striped:
red/green = ?
red/blue = ?
are these wires in the GTV plug or on your new headunit?

do not presume anything, especially with wires in a car's plug. :)

you need a multimeter to help work it out. i actually thought the GTV had ISO plugs, and followed the same wiring pattern as outlined in the 147/156/GT install thread.

with your multimeter, you can determine:
*constant +12V powerwire (main wire to run headunit; new HU usually has yellow powerwire for this connection): set MM to 'DC voltage' in the '20V' range or similar (to measure ~12V); have ignition key OFF; put the black (NEG) probe on a known ground point (ie: bare metal somewhere in the car); use the red (POS) to probe the wires in the GTV plug (ignition key off); i expect there to be only one pin/wire that provides +12V
*switched/ignition/ACCessories +12V powerwire (accessories wire to trigger HU on/off with ignition key; new HU has red powerwire for this connection): after finding the above wire, now turn the ignition to ON; use the red probe to find the new wire that has now switched from 0V to 12V (black probe still grounded)
*groundwire: set the MM to 'continuity/beep' mode (when the red and black probes are connected together, the MM beeps, to confirm a continuous electrical connection); now use the red probe to find the pin which makes the MM beep; this is the groundwire, and has created an electrical connection with the black probe

the other wires may relate to:
*illumination: when you switch the side/headlights on, this wire goes from 0V to +12V
*antenna trigger wire: this is probably the remaining wire; if so, it goes to the antenna to activate a booster for the signal; you need to connect the ANTenna output wire from the new HU here (ie: turn on the HU, and this output wire provides +12V to trigger the booster)

I've also got to make a connection to the parking brake (do to the safety mechanism on the unit stopping any viewing the screen while the car is moving), does anyone have any pointers on how I can easily find the parking brake wire. I'd love not to have to strip my dash apart if possible.
the wire is best accessed where the handbrake is. it's the same set of wires that trigger the little dashlight to say the handbrake is 'pulled'.

normally, HUs like yours require this wire to be grounded. you can cheat by permanently grounding it. however, if you do it 'properly', you need to locate the handbrake wire, and determine which one goes to ground when the brake is pulled.

:)
 

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Discussion Starter #3
Thanks Shiny.. :)

To clarify, the wires Im referring to are the ones in the GTV plug. I've referenced the HU manual to label each of the wires on the HU plug and loose wires.

First thing tomorrow I'll go and get a multimeter and report back.

Unfortunately, It looks like I may have spoken to soon, and I messed something up in the car as although I only tried connecting the wires up once before I wrote in, when I closed the car up I found now the alarm unit isnt responding..! :( cant believe I screwed something up so quick.. remote works, car starts, just the alarm unit doesnt respond. must have messed something.... i swear i hardly touched anything.. .
 

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Discussion Starter #4
Finally got back to doing this,

By the way, Great instructions Shiny.. as always terrific help.

I thought I would list out what I found for any other GTV P2 owners who want to do their own wiring. This is what I found on mine anyway.. (remember this is for the plug in the alfa, not the head unit):

red = constant
red/blue = also a constant
Black = Ground
yellow/black = illumination
red/green = undetermined, but deduction dictates probably power antenna trigger wire
(There was a switched/ignition cable into the stereo, but someone down the line had routed it from a plug and set of wires into the centre console)

I searched around under and around the dash and I found two unused plugs, one plug was a constant and ground, the other was a switched and I think a ground (very 'weak' connection). so I'm happy cos I can things other than my HU without having to 'share' connections.

Now onto a question for anyone who can help..
I have a expansion box specifically for my head unit, the box is a alpine KCE-104v. As well as the usual constant, switched, and ground; There are two cables which are puzzling me. I;ve searched online but as this product itself is not common cant find too much. Rear select doesnt seem to mean much either based on my searching. This is what the manual for the expansion box says about the two cables/connections:

Rear Select 1 Lead (Grey/Pink) - Connect to the ground with a push switch etc
Rear Select 2 Lead (Black/Pink) - Connect to the ground with a tact switch, etc.

WHat are they for, do i need to do them, relevance etc, anyone with any ideas?... thanks...
 

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AO Silver Member, 155 Lounge Winner 09
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do you have the manual? if not: http://www.alpine.com.au/downloads/web_owners_manuals/KCE-104V.pdf

from what i can gather, those two wires can be grounded via switches, allowing 'momentary' grounding (eg: push-button switch; if you hold the button down, it grounds the wire): SEL1 > switch > GND

this allows you to enter the setup menu and toggle through the selections.

:)
 
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