Monday 18 December 2017

Chrysler - Audio system, amplifier and head units

I've finally got round to getting my new Android head unit for the car (Thanks to my wife for my birthday present!) and so this has got me onto figuring out the audio system for my Chrysler Grand Voyager, and boy is it not simple!
Firstly, a standard ISO harness/converter adapter won't work as I've found out before when trying to fit my Bluetooth Parrot phone kit ( )

So I'm now starting to look seriously into how to wire in a new head unit, taking the back off the existing head unit I find the usual block of audio wires which are:

  • Front left (+/-)
  • Front right (+/-)
  • Rear left (+/-)
  • Rear right (+/-)
So I started out by modifying (cutting!) an ISO harness cable, that lets me disconnect one by one the wires and then feed in an alternative audio source. That way I can test each speakers input and feed it to make sure audio works.
I started by disconnecting the rear left output wires, and NO DIFFERENCE! Rear left still worked. I then did the same to rear right and again nothing happened, rear was still working! Playing with the fader and balance on the radio and it managed to still fade between front and rear, left and right. How odd! So next I cut the front left, and BOTH front and rear went off. Doing the same to right and the same, both front and rear went off.
I then fed new audio into front left and audio started to come out of the front and rear speakers correctly, doing the same to right showed the same. So this looks like it's ONLY feeding a left and right signal to the amplifier.
Now I do know this car has an amplifier hidden in the rear panels of the car, so next job was to locate it and see what it was up to!
Taking apart the rear panels I found the amp tucked away in the right hand side behind the speaker.
As you can see that also identified the speakers as Infinity, which nothing else had pointed to until this moment, so another point is to check the back of the speakers. I couldn't find any official specs for these, but testing I found them to be 2ohm speakers (Which is quite low, and would fit with them being decent/high performance. But bear in mind that means you need a decent amp/head unit to power them).

You have to take quite a bit of the panels off to get at it, unless you can contort your hand into the panel to get at the fastening nuts (I did this in the end!)
Here is the amplifier out of the mounts, at the top are two connector blocks.

You can see the two connector blocks (I'd removed one) and at the top right of photo is the connector for the rear right speaker I'd disconnected to get into the hole where the amplifier was.

The connector I've removed (I'll call it the right side connector) contains MOST of the speaker outputs. This car has 8 speakers. Front left (top speaker), front left (bottom speaker), front right (top speaker), front right (bottom speaker), rear left (top), rear left (bottom), rear right (top), rear right (bottom). The more observant of you will spot only 6 speaker pairs on that connector, they continue on the other connector (Chrysler mustn't be able to source connectors with more than a certain number of pins!).
So by feeding audio into each of these I discovered these directly drive the speakers around the car, and so can send audio to speakers direct, irrespective of if the ignition is on, amp is on, etc, which is good news.
Now I started to look into the audio from the head unit and by testing and following wires I found 4 wires coming from the head unit, left (+/-) and right (+/-) so that matched my findings that the amp simply got a left and right. So how did it handle fader/balance? The answer was on one of the other mystery wires.
There were 2 black (Both ground) 2 yellow with red stripe (Both had 12v constantly, irrespective of ignition or radio on or off) and a further two wires. One is white with a purple/violet stripe. This is the interesting wire as it doesn't show a voltage or anything. My suspicion is this is the CANBUS network data wire, and is sending digital data from CANBUS to the amp to interpret. That means the existing head unit will be sending a message into CANBUS (Power amp on, fader volume level, left/right speaker levels, etc) and the amp is then reading and responding to these commands on it's own.
That means a simple head unit swap isn't going to work, as firstly nothing will be telling the AMP to turn on, secondly even if it was turned on it wouldn't control the fader/balance settings.

That leaves me with two choices:
  • Run a wiring loom from the new head unit at the front, round to where the factory amp is, remove the factory amp and wire direct into the speakers. That way the new head unit completely controls the speakers direct and avoids the amp
  • Replace the factory amp with my own, still just use left and right (So new head unit couldn't control fader between front and rear) but it would be amplified output to the speakers.
At the moment I'm unsure which option to take.

So I've started to document the wiring I've discovered.
Here is the connector at the infinity amp end. As above I'm calling them connector 1 and 2, connector 1 on the left of the photos above mainly contains power and inputs, and connector 2 mainly speaker outputs. So the connector wiring goes like this:
PINConnectorwiring colourFunction/use
x1green/blue stripeFront Left top +
x1green/yellow stripeFront Left top -
x1grey/blue stripeFront Right top +
x1grey/yellow stripeFront Right top -
x1yellow/red stripeConstant 12v + supply
x1blue/pink stripeignition 12v + supply
x1white/purple stripeCANBUS/Data supply
x1green/orange stripeFrom radio left channel +
x1green/blue stripeFrom radio left channel -
x1grey/orange stripeFrom radio right channel +
x1grey/blue stripeFrom radio right channel -
x2black/green stripeFront left lower +
x2greenFront left lower -
x2grey/brown stripeFront right lower +
x2greyFront right lower -
x2grey/green stripeRear left main +
x2light greenRear left main -
x2green/light green stripeRear right main +
x2green/grey stripeRear right main -
x2green/pink stripeRear left upper +
x2green/blue stripeRear left upper -
x2grey/yellow stripeRear right upper +
x2grey/blue stripeRear right upper -

And now the head unit wiring:

The plug looks like this:

So I've documented what I've found:
PINChrysler wire colourISO/Aftermarket harness colourAftermarket head-unit colourFunction/use
xgreen/orange stripen/aWhiteFront Left +
xgreen/blue stripen/aWhite/BlackFront Left -
xgrey/orange stripen/aGreyFront Right +
xgrey/blue stripen/aGrey/BlackFront Right -
xblue/pink stripen/an/aIgnition +12v
xwhite/purple stripen/an/aCANBUS data line
xorangeorangeorange ILLIllumination
xredredRed Acc-inIgnition/switched +12v
xyellowyellowYellow B++12v constant
xblackblackBrown/Black and Black-12v ground constant

A couple of other points, I've noticed quite a few wires with black electricians tape (Not the fabric factory-fit type, but aftermarket, like the stuff I use!) around wires, notably around the factory amp speaker outputs, in the head unit, etc. I've also spotted a RED wire coming out of the head unit that goes off into the front bulkhead. I'm now wondering if this goes off to the fusebox and to the NBS relay. This is apparently the relay that switches the amp on and off (It stands for Name Brand Speakers, i.e. the infinity system) so I'm going to check as my guess is this car has had an alternative system in at some point and the relay was forced on when power was given to the radio (Or ignition) so I'll check that relay out.
That makes me think replacing the factory amp with aftermarket might be the way to go without having to rewire the entire car.

This is constantly a work in progress, so hopefully it's useful and I'll keep adding to it as I do more and get further on my path!


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