: 05: Want to add sat radio. no Bose/NAV/RSE with 6 cd changer

04-20-09, 08:53 AM
Hi all,

I recently joined and have been looking for info on adding satellite radio to my wife's SRX. It is an '05 with the 6 disc changer. No Bose, no NAV, no factory XM. I have been searching for forums for a couple of hours and most of the posts detailing this kind of thing are missing the pictures or detailed writeups. Maybe my search ability is lacking this morning.

I pulled most of the interior apart Saturday to get an idea of exactly what I was dealing with. Behind the head unit there are two 8 pin connectors. One of which is the power. Of the sixteen pins there only 7 or 8 are connected. There is also a 20 pin connection built from three segments. Of the 20 pins 5 or 6 are connected. I have pics of these on my camera so I can get colors and pin position and such.

Behind the rear passenger side panels I think I found the plug that would normally be the connection for factory XM. I did not take a picture of it, but it is white and had several purple wires connected to it. I think it had 8 purple wires. From reading on this board it seems that the purple wires are for the cars bus system.

Behind the rear driver side panel is the amp for the radio system. I might have to tap into that connection for the sat radio. I would love if someone who has done this could give me any info. I am not afraid to cut wires and splice in new ones if need be.

Thanks for any info!

04-20-09, 09:59 AM
I pulled the pictures of the HU plugs. They are attached to this post.

If anyone knows what kind of plugs these are maybe I could buy a spare set and make a pigtail rather than cut the factory plugs.

If someone has the schematic for this radio that would be very helpful.


04-20-09, 12:15 PM
I found the schematic at a website that I am unable to link to. With the schematic, I was able to get the pinouts for the factory radio (U2S):

Radio Connections (U2S)

C1 = 20 pin yellow/green/blue
C2 = 8 pin brown
C3 = 8 pin grey

Factory with no Bose or XM

8 - Class 2 Serial Data (Purple)
11 - Class 2 Serial Data (Purple)
2 - Bare - drain (wrapped in tape at connector)
3 - Right front low level audio (+) (Light Blue)
4 - Right front low level audio (-) (Light Green)
5 - Left front low level audio (+) (Tan)
6 - Left front low level audio (-) (Dark Green)
8 - Bare - drain (wrapped in tape at connector)
2 - Not on schematic - Purple - (Class 2 Serial Data???)
7 - Battery (+) - (Red/White)
8 - Ground (-) - (Black/White)

Radio connections with factory XM (U2K). These are in addition to the above wires.

3 - Remote Radio Output (-) (Dark Green/White)
4 - Remote Radio Left Audio Signal (Tan/White)
6 - Drain
7 - Remote Radio Right Audio Signal (Brown/White)

I also have the pinout for the factory XM (U2K) when added to the U2S radio:
Radio Connections (U2K)

2 - Remote Radio Left Audio Signal (Tan/White)
3 - Remote Radio Right Audio Signal (Brown/White)
9 - Ground (Black)
10 - Remote Radio Audio Output (-) (Dark Green/White)
15 - Class 2 Serial Data (Purple)
16 - Battery (+) (Red/White)

Coax - Sat Antenna
Coax - Sat Antenna

Now the million dollar question is where do I tap the Class 2 Serial Data line at? Does it matter can I just tag onto one of them?

I plan on getting a male and female version of the 8 pin grey connector for the factory radio. I will need to add four pins to it for the Sirius SIR-GM1 radio. I will also use the battery (+) and ground (-) from that connector. The only other thing I will need is the Serial Bus line (purple). There is a purple wire in the factory plug that is not on the schematic I have. Can I just use it?

I still want to look at the SIR-GM1 wiring again to make sure I have the right wires, but I think I do.

After reading over this post and double checking my schematic, the C3-7 wire has two assignments. Battery (+) and Remote Radio Right Audio Signal. I need to do more research, but I think this schematic is wrong.

Anyone have any ideas about the serial data line or suggestions?


04-21-09, 09:29 AM
The SIR-GM1 kit has an adapter designed to connect to the factory XM connection. I found a replacement plug that should allow me to make my own "factory" XM connection. I can not yet create links, but the website is keefe performance dot com. The connector is a Delphi Micro 64 connector. Some Googling should produce other vendors.

I am still looking for the plugs that fit the back of the stock HU. They are 8-way F Junior Timer Type. If anyone knows where I can order one I would appreciate it.


04-21-09, 10:50 AM
Instead of finding a compatible plug (female and male ends) to make a pigtail, I can simply get the correct pins and insert them into the factory plug in the back of the radio. I can then connect the other end of those pins into the matching plug for the SIR-GM1 pigtail.

For reference the factory C3 plug on the radio is made by AMP/TYCO. It is part number 963120-1 8 (4x2) pin Junior Timer connector. One possible terminal is AMP number 964201-1. The terminals seem rather hard to locate. I did find a website (eagleday dot com) that sells a 10 pack for $9.95. I can add four pins to the factory plug and connect them to the Sirius radio. I will also need to tap into the power and ground in the same plug. That only leaves the Class 2 Serial Data connection.

I think I need to search the forum more. It seems to be common, but so far my searches have not provided the necessary info as to where to tap that line.


04-24-09, 07:43 AM
I found the diagram of the Data Link Connector that shows where the factory Serial Bus connection for the XM radio is. There is a connector (SP304 - Splice Block 304) that connects to the Rear Integration Module and several other circuits at the rear of the vehicle. All the Class 2 Serial Data Connections are just hooked together.

From that it seems like I can just hook into one of the data bus lines behind the radio. My AMP Junior Timer connector pins have arrived, but I am still waiting on the female connector for the factory XM.

The SIR-GM1 came with two harnesses and I may just cut one of them up this weekend to see if I can get the wiring connections right.


04-24-09, 10:43 AM
After more research I have to decide what to do about the Class 2 Serial Data line for the SIR radio. I found the pinout of the SIR-GM1 plug. In case anyone does not have it here it is:

From the wire side of the plug with the lock facing up, pin 1 is on the left on the top row. Pins 1 through 5 are the top row and pins 6-10 are the bottom row.

Here is my bad ASCII art of the wire side of the plug.

L = Locking tab
1 = L Audio (+)
2 = Common Audio (-)
3 = Ground (12v-)
4 = Class 2 Serial Data Out
5 = Battery (12v+)
6 = R Audio (+)
0 = Class 2 Serial Data In

Because I plan to install the Sirius behind the factory HU I will need the serial data in and out. Of course I could run a wire all the way back to the Rear Integration Module, but that might pick up interference.

Here is the pinout I plan to try first:

Factory 6-cd changer
C3-1 -----------> SIR-GM1-6 R Audio (+)
C3-3 -----------> SIR-GM1-1 L Audio (+)
C3-4 -----------> SIR-GM1-2 C Audio (-)
C3-7 ---tap-----> SIR-GM1-5 Batt (+12v)
C3-8 ---tap-----> SIR-GM1-3 Grnd (-12v)

C1-8 disconnect from factory HU and connect to SIR-GM1-0
SIR-GM1-4 -----> C1-8

I might have the left and right audio lines swapped, but that would be an easy fix if everything else is correct.

I should be able to test things this weekend. I will post next with my success/failure.


Sean L
06-15-09, 07:41 AM
Just curious....Did it work?

I'm looking to do the same thing.


06-15-09, 11:00 AM

That may help, you may need to add pins to the factory harness but you should get the info you need.