This is a how-to article on how to upgrade to the 2012-2013 GM HDD Navigation head unit for any 2007 to 2013 GMT900 Truck/SUV (except Escalade).
First thing you need to get is the head unit itself. I got mine from eBay and the seller said it came from a 2012 Chevy Tahoe. Once I received the unit, I hooked it up to my truck and got to the “LOCKED” screen since the theft lock is still VIN matched to the previous vehicle. This was just a quick test to see if the unit would even power up and to check to see if the screen was damaged in any way. Everything looked good so at this point, the head unit will need to be programmed to your vehicle VIN. I had this done by Greg at CPS Audio Video in California. I shipped the unit out to him and had him program in my VIN as well as make sure the rear view camera feature was activated along with rear seat entertainment (RSE) and rear seat audio (RSA). Also had him give the unit a general check over to make sure everything was working correctly. Turnaround time was very quick (they received it Thursday and had it shipped out Saturday). Greg also sells the harnesses to make all this plug and play as well an amp if you don’t have the Bose system in your vehicle. So you can go this way if you like. I have worked in car audio for many, many years so I wanted to tackle this myself and build my own harnesses so I would have a better understanding of the system overall and to help explain this retrofit to you folks!
Once you have the head unit programmed, you are going to need to get the harnesses built (or purchase them). The main harness on the radio is a new 44-pin connector called X1. There is no X2 connector on this radio. The X3 harness is for the rear seat entertainment and has video / audio signals that need to go to the rear seat display in the overhead console or front seat headrests. The X4 connector is for the rear camera input as well as the vehicle speed sensor (VSS) signal and voice control of the radio. Then you have three (3) antenna inputs on the radio. The black antenna input is for the standard AM/FM antenna. The Blue antenna connector is for the GPS antenna. And finally, the beige antenna connector is for the XM Radio Antenna. That’s right; the XM radio module is integrated into the Navi unit. So when you get this all up and running and you want to use XM radio, you will have to call them to give them the new Radio ID number as the old XM radio box will not be used anymore. Usually they should transfer you to a new Radio ID without charge (tell the XM folks that the old XM radio box was faulty and that the service shop changed it out for a new one and you need to activate it on your account) but depending on the agent you get, they may want to charge you for this. Finally, there will be a USB connector on the back of the Navi unit. If you are coming from a 2010 or earlier vehicle, you will not have a USB connection on the dash or in a storage compartment. You will need to add this to your vehicle if you want the USB functionally (and you will - it is good for USB flash drives as well iPod control). And that covers the connectors on the back of the Navi unit. We will now discuss each one in detail and how to retrofit them to your truck’s connectors.
My truck is a 2012 GMC Sierra SLE with the 40/20/40 front seat. Since I have this seat, I do not have the center console. The center console is available for my truck, and is where they stick the Bose subwoofer and amp. Since my truck did not have this and I really do not want to put a center console into my truck, it goes without saying that I do not have the Bose system in my truck. The Navi radio does not have an amplifier built-in and therefore requires an outboard amp. Upon taking my radio out, I only have 4 connectors available to me. My truck X1 connector is a black 14-pin connector. The X2 connector is a yellow 16-pin connector. Then I have a USB connector and my AM/FM Antenna connector. There is no X3 or X4 connector, GPS antenna or XM Radio antenna connector. So, we need to make an adapter to adapt my X1 and X2 connectors to the 44-pin X1 connector on the Navi radio in addition to allowing the use of an outboard amp. I will tell you that I actually tried a Bose amp in my system. Since the speakers in my truck are not the Bose speakers (Bose speakers usually have a 2 ohm rating and I am sure the speakers in my truck are rated at 4 ohms), the amp did work but the sound was not very loud and was very “thin” and lacked bass and body even after adjusting the tone controls. The Bose amps do have some EQ circuits in them and depending on the Bose amp you get, it can be for an extended cab, crew cab or SUV application and the EQ is different for each. The amp I used was a Bose Crew Cab amp. I did not have a Bose sub either so this did not help the situation. The sound was there but it was horrible at least to me and I abandoned using the Bose amp for my application. I decided to use an aftermarket amp (in my case a Rockford Fosgate PBR300X4 75 watt x 4 channel amp) to drive the factory speakers (I fully intend to change to aftermarket speakers and add a sub or two in the back at a later date and the aftermarket amp would be better for this in the long run) . I chose the Rockford Fosgate PBR300X4 since it is a tiny amp and this would allow me to mount it in the dash somewhere (more than likely where the old XM Radio box was located behind the glove box) and it has a speaker level turn on feature that will allow the factory chimes, Onstar and Bluetooth to function even though the radio may be off.
All right, as mentioned earlier, my truck has 4 connections that go to the factory radio. X1, X2, the USB connector and the AM/FM Antenna connector. The connectors really need to understand of course are the X1 and X2 connectors. The AM/FM Antenna and the USB connector will be adapted to the Navi radio without any cutting or soldering. So let us take a physical look at these connectors:
X1 Connector
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X2 Connector
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The navigation radio has seven connectors on the back: X1, X3, X4, AM/FM Antenna, GPS Antenna, XM Satellite Antenna and the USB connector. There is no X2 connector on the navigation radio as those function have now been included in the new 44-pin X1 connector. Let us take a look at this connector:
X1 Connector on Navigation Radio
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Now we need a pin out diagram so we can see what wires do what and where we need to re-route the wires from our factory connectors (X1 & X2) to the new navigation radio X1 connector (note the grayed out boxes are not used in my application, so I need to use 7 wires from my truck X1 connector, 6 wires from my truck X2 connector, and we will need to use 15 wires to/from the navigation radio X1 connector:
Pin
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Truck X1
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Truck X2
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Navigation X1
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1
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Battery + Voltage
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XM Left Audio +
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Not Used
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2
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Left Front Speaker +
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XM Right Audio +
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Not Used
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3
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Right Front Speaker +
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Not used in my truck
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Not Used
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4
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Not used in my truck
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Not used in my truck
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Not Used
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5
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Not used in my truck
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Left Rear Speaker +
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Not Used
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6
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Not used in my truck
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Right Rear Speaker +
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Onstar Audio -
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7
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LED Backlight Dimming Control
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Onstar Audio +
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Not Used
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8
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Ground
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Not used in my truck
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Not Used
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9
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Left Front Speaker -
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XM Left Audio -
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Not Used
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10
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Right Front Speaker -
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XM Right Audio -
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Not Used
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11
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Not used in my truck
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Shield For XM Audio Wires
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Not Used
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12
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Not used in my truck
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Not used in my truck
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Not Used
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13
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Low Speed GMLAN Serial Data
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Left Rear Speaker -
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Not Used
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14
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Not used in my truck
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Right Rear Speaker -
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Not Used
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15
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Onstar Audio -
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Not Used
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16
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Not used in my truck
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Not Used
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17
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Not Used
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18
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Not Used
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19
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Not Used
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20
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Onstar Audio +
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21
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Not Used
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22
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Not Used
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23
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Not Used
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24
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Not Used
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25
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Not Used
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26
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Not Used
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27
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Not Used
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28
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Low Speed GMLAN Serial Data
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29
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Front Audio Shield Wire
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30
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Rear Audio Shield Wire
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31
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Low Level Right Front Audio -
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32
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Low Level Left Front Audio -
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33
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Low Level Right Rear Audio -
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34
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Low Level Left Rear Audio -
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35
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Not Used
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36
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Not Used
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37
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Amplifier Control
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38
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Ground
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39
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Low Level Right Front Audio +
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40
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Low Level Left Front Audio +
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41
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Low Level Right Rear Audio +
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42
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Low Level Left Rear Audio +
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43
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Entertainment Remote Enable Signal
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44
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Battery + Voltage
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Pictures of my truck X1 and X2 connectors:
Truck X1 Top
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Truck X1 Bottom
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Truck X2 Top
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Truck X2 Bottom
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I picked up a reverse connector kit for the truck radio connectors from here:
$4.49 with free shipping. The connectors look like this:
I do not use the red Accessory wire and I actually take the connector apart and take out the wires I don’t need and /or reinsert them into positions that I do need. The X1 connector has wires in positions 4, 5, 6, 7, 11, 12 and 14 that I will not need so I took them out. I reinserted two of these wires I took out of the X1 connector into the X2 connector into positions 7 and 15 to get the Onstar audio into the navigation radio.
Now the problem is where to get the X1 connector for the navigation radio. There really are not audio install kits yet that have this connector. However, you can get the 44-pin harness with all the extra wires in it from the PAC Audio product AA-GM44. This is an Amplifier Integration Interface adapter that allows you to add an aftermarket amp to a GM car that already has a 44-pin radio installed. What I did is again take the connectors apart and take out the wires that I don’t need in this application to make the harness more manageable. This product can be found from several vendors under $40. You will get both the male and female sides of the connector; you will only be using the female side. Take the female connector apart and take out the following wires from positions 1, 2, 3, 4, 5, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 24, 25, 26, 27, 31, 32, 33, 34, 35, 36, 37 and 43. Pins 31 – 34 are the low level audio output (-) wires and they are spliced close to the connector body for the T-harness to the SOME-4 line converter. We need some more wire length for these wires and so you will put back in the wires that you removed from pins 35, 36, 37 and 43 into pins 31, 32, 33, and 34 to get much more length so we can splice into the harness like 5 inches away from the connector body to give the harness more room to move and fit into the area in the dash.
Unfortunately you will not be using the SOEM-4 line output converter in this application so you can sell it or toss it. You might ask why we can’t use it to hook up our external amp. There is not really an output from the radio that will come on whenever the radio wants to output audio. The radio can be off and still send out chimes. Since the chimes come from the radio, we would need a signal to tell the outboard signal processor to turn on in addition to telling the amp to turn on. I have not investigated this method further as the amp I am using will turn on whenever there is audio output from the radio so I don’t need the line converter anyway. It is just the cheapest way to get the required 44-pin female connector with all the pins populated so we have extra wires to lengthen the harness for our splices. The AA-GM44 product looks like this:
Once you have the wires inserted into the female 44-pin connector, you can reassemble the female connector and replace the big white wire retention lock. Now we can solder / heat shrink (as I did in my case) or you can use butt connectors and crimp the wires from the reverse truck connectors to the navigation connector. Five wires are direct connections, but for the audio signals, we need to create our own harness to go to the outboard amplifier. In any case, you can connect the following wires directly between the reverse truck connectors and the navigation connector:
Wire Function
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Truck X1
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Truck X2
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Navigation X1
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Battery + Voltage
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Pin 1
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Pin 44
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Ground
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Pin 8
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Pin 38
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Low Speed GMLAN Serial Data
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Pin 13
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Pin 28
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Onstar Audio +
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Pin 7
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Pin 20
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Onstar Audio -
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Pin 15
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Pin 6
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I would splice these wires at least 4 inches from their respective connectors to give us plenty of length to work with. Next we will need to wire up our amplifier input and output harnesses and I will leave that for the next post. Hope you enjoyed reading about this modification thus far and looking forward to the next installment. Until then...
