Installing OEM XM unit. PCM?

R34P3R · January 29, 2014

I own an 07 classic Silverado that did not come with the factory XM unit. I pulled one from a Tahoe at a junkyard a few days ago. I also took the harness which i assumed i would be needing but I had to snip off the end that runs behind the gauge cluster. I'm told that the end i snipped runs to the PCM. This is where my problem is... My truck is a 4.3L V6, which i assume has a different pinout than the average Silverado. I've spent hours and hours trying to find pinout diagrams but cant seem to find any for a 4.3L that comes with the factory XM unit. So... I'm stuck... can anybody point me in the right direction for this project?

I'm not trying to use the XM unit for its intended purpose. I'm hijacking the XM harness for an auxiliary port that I'm installing. I want the "band" button on my factory radio to do its part and switch between FM and Auxiliary. Problem with that is that the radio wont do that if the XM unit doesn't have its "Serial Bus" connection.

Also I've accidentally managed to connect my phone to the factory radio. At first i thought i had succeeded with the auxiliary attempt but soon noticed that the volume was a bit too low. Not even a pre-amp could help solve that problem. ....but the phone works fine tho. Ask me how i did it if your interested. just don't expect professionalism lol.

bird38 · January 30, 2014

If i remember right once an XM module is installed it vin locks and is only good for one vehicle. Cant seem to remember why... So your used xm model out of that TB is no good.

You can buy the kit new and either have your dealer install or just install yourself. GM part number 20940402 is for an XM upgrade kit for 07-11 trucks. But you will want to verify your VIN or the RPO code for your factory installed radio. This kit is for trucks with RPO Code UE1, but without any of the following RPO Codes: UBS, UM7, U1C, U2K. RPO codes are found on your window sticker, or a label in your glove box.

R34P3R · January 30, 2014

Your correct on the Vin lock. But I know for a fact it can be swapped with another one whether new or used. Guy I know says it's unlocked by means of "flashing" or something of that sort. I understand the dealership CAN but WILL NOT do this for a reason of which i really don't have a care. They'd probably charge me an arm and a leg to do it anyways. So yeah I'm just trying to get a PCM pinout for that particular model. Thanks for your time and input though

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bird38 · January 30, 2014

Tried to look on alldata for you to get some wiring diagrams but my previous truck (07) has since expired and the new models are different. Maybe another user that has a subscription can help you out.

Also if you find your xm box is locked (im sure it is) there is a solution by cutting 4 leads to a chip inside the module.

R34P3R · January 30, 2014

Sweet! Thanks a bunch!

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montyss · January 30, 2014

this place in the link can supposedly clear the VIN from XM modules so once back in your truck it will accept that new VIN , they charge $35

http://www.instrumentsales.com/

hzhardy · January 30, 2014

pm sent with wiring diagrams

R34P3R · January 31, 2014

Okay so here is what i've done:

I connected the light green wire (serial data c2271) to pin #2 on the OBD connector (serial data c1132).

I connected the black and white wire (ground c1851) to the chasis.

and then i connected the orange wire (positive voltage c340) to a 15 amp fuse and the other end to the Wipers through the fuse box.

aaaaaaand nothing. I double checked my connections. Voltage was good.... but no dice.... any suggestions?

hzhardy · January 31, 2014

the diagram shows two black white wires, one is the radio ground the other is the signal ground

hzhardy · January 31, 2014

the one all the way to the side pin 9

hzhardy · January 31, 2014

and you tapped into the purple wire on the obd connector?

R34P3R · January 31, 2014

yeah the purple one. Pin 10 is the signal sound and that goes to the radio. pin 9 is the ground which i grounded to the chasis.

R34P3R · January 31, 2014

I'm thinking the XM unit might be dead. I own a multimeter but I'm not very experienced with it... how would I go about checking the unit for a good circuit?

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hzhardy · January 31, 2014

I'm thinking the XM unit might be dead. I own a multimeter but I'm not very experienced with it... how would I go about checking the unit for a good circuit? Sent from my SM-N900V using Tapatalk

you would not be able to trouble shoot the circuit without opening it up and haveing the schamatics to test each individual component