12-29-08, 06:05 PM
I have an 07 escalade and my ONSTAR module (located behind the radio) was stolen. I have not been able to get a new one yet, but i was wondering if anyone knows if it is possible to get the XM antenna connected to the XM module (located behind the glovebox) without using the onstar box ?
There are 2 antenna wires going into the onstar module (both SMB connectors) One is purple and one is blue. One antenna wire is alot heavier gauge so im gussing that this is the one that goes to the roof. I tried making a male to male SMB adapter and hooked the 2 antenna wires going into the onstar box together but i still get "CHECK ANTENNA" message when trying to get the XM radio to work
Everything in my truck is factory - Im just not sure if there is any other place that the antenna could be disconnected.
Anyone have any ideas ?
12-30-08, 02:36 AM
There should be 3 connectors going to your roof antenna. I know there was a Blue (OnStar GPS), Purple (OnStar Cellular signal) and Yellow (XM). The two connectors going to the VCIM should be irrelevant to the XM.
12-30-08, 11:46 AM
I only have 2 antenna wires behind the radio for the Onstar module, one is purple and one is blue. I believe that the yellow one runs from the XM box (located behind the glove box) and splices into either the purple or the blue antenna wire and runs into the onstar box.
You can see from the image provided by GM that #3 is listed as the antenna cable that runs from the XM module to the OnStar module and then to another connection which then runs to the roof.
So from this I am guessing that the YELLOW XM antenna plug/wire splices into the purple or blue one somewhere in the harness that runs from the XM module to the Onstar module.
Any ideas ??
12-30-08, 12:28 PM
They probably just meet up in the same harness and are bundled together, not spliced. That's how the older models were. I would check the connections where the upper cable and lower cable meet. Unfortunately I don't have factory service info on the 2007+.
12-30-08, 03:11 PM
Yea thats what i figured, so if they meet up somewhere in the harness and then go into the Onstar module then there is the purple antenna plg that comes out of the Onstar and goes to the connector under the top dash pad and then runs to the roof. I checked this connection and it seems fine. So i would imagine there is some type of data that is supplied by the Onstar module to the antenna in order for the antenna to function.
12-31-08, 09:38 PM
there wasn't in the older Escalade. All three functions operated independently. In fact I'm using an antenna from a '05 STS in my old chevy for XM without the other 2 leads hooked up at all. When I got the cable from that (or a CTS, can't remember) it was 3 cables bundled together. i just separated them. They never spliced together.
did you wind up figuring this out? I'm considering disconnecting my onstar antenna and would be nice if it was as easy as removing one cable... let me know what you found. I'm also using XM right now so would like to keep it. looks like they both share the same antenna on the roof.