GPS Signal after On-star digital upgrade
 

I've been lurking here for a while but can't find anything on my problem. Bought my '03 STS over two years ago. First thing we did was tint the windows. All's well, and works, so far. Took the car in for the On-star digital upgrade and now the GPS doesn't want to sync up. We can go out and it will never sync. My wife now calls the GPS the boat anchor.

The techs at the dealer blame it on the tint. They say they took the GPS antenna out of it's normal location and it works very well when out from under the tint. I have worked w/ GPS systems for years and know that if the antenna lead isn't tight or misplaced slightly behind metal it will affect the performance. Exactly where is the antenna on this car? Could I put another remote antenna on it. Where is the GPS unit? I know there is at least one diagnostic screen but don't know how to get to a GPS performance/satellite location/antenna performance screen to check antenna location. Anybody know anything on the available screens?

Thanks for any responses.
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RE: GPS Signal after On-star digital upgrade
 

Onstar configures car, by satellite. The composition of the tinting material maybe part of problem. GM published info that tinting and /or other objects, metal obstructions can cause degraded performance. Request Do***ent ID: 1600906 from local dealer.

RE: GPS Signal after On-star digital upgrade
 

I'll check that do***ent with the dealer. The problem is the tint has been on for two years and we didn't notice any difficulties with the GPS performance. It was only after the On-star upgrade, about 3 months ago, that we noticed the difference. Would they need to access, move, or otherwise have to deal with the GPS to do the upgrade? I know there is an interface of some sort between the On-star and the GPS.

The reason I asked about the antenna location was so I could make sure it was properly placed and no metal obstructions were in the way. From experience, an inch one way or the other can make a big difference in antenna effectiveness.
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RE: GPS Signal after On-star digital upgrade
 

Vehicle Communication Interface Module is changed during upgrade. Antenna location doesn't change. You could have problem with gps jumper where it attaches to VCIM. Connector can be damaged during upgrade on 02-early 03 Sevilles.

RE: GPS Signal after On-star digital upgrade
 

Thanks for the response, sorry I couldn't get back sooner.

Where is the VCIM located so I can check the connectors. This is exactly the kind of problem I was anticipating.
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