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GPS no signal

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2015 Suburban LTZ w/42,000 purchased new in Dec 2015 (~2.5 years in service)


In May 2018, my Sharkin antenna failed (antenna was completely filled with water).  I'd bet this is also your issue (GPS showed me in middle-of-nowhere, and normally green OnStar Light glowed red).


It is a well-know issue for which GM offers a customer satisfaction program to repair at no cost.  Though, despite my year and model of vehicle being included in program, GM insisted (based on VIN) that my vehicle is not covered, and this was an out-of-pocket repair for which GM offered zero assistance.  


Dealer quote $600 to repair but finally agreed to do repair "at dealer cost" for $400.  


When antenna failed, prior to dealership replacing, water flowed from gasket between antenna housing and roof when pushing slightly on antenna cover.  Despite obvious water issue (I kept antenna, and it is still filled with water over 2 months later), GM refused to acknowledge that is it related to GM customer satisfaction campaign issue.  Maybe you are lucky, and your VIN will be included.  


I would recommend pushing slightly on antenna cover as I did while recording video with your phone.  Maybe if your VIN is also not included, GM will have harder time saying it is not same water intrusion issue. 


Good luck. 

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  • 2 months later...

Disclaimer - I'm not an "auto body repair', nor do I play one on TV. 


When I replaced my shark fin antenna, my dealer service advisor printed out a copy of the replacement procedure for that,  and it called for 3M Flexiclear Body Seam Sealer 08504 (in my case...available though Grainger).


"Excellent for Exterior Automotive Sealing 
3M™ Flexiclear™ Body Seam Sealer is a caulkable exterior sealer which adheres to surfaces such as primed and painted metal, glass and aluminum. Our sealer dries clear and resists yellowing for a clean, low profile appearance. It uses a standard "caulk" style dispensing system. It's fast drying and ready for painting in approximately 45 minutes."


Most Silicone's are generic, and fail over time (for several reasons)


Personally, I have too much invested in my ride to go the cheap route, especially for a roof mounted device that could potentially leak.


I used the recommended 3M Seam Sealer and have had NO issues, my truck goes through a car wash weekly (sometimes more).


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  • 3 years later...

Our 2015 Tahoe GPS just started showing the wrong position. It has us about 40 miles off, and, in the upper right of the screen are the letters "GPS" with a red X through them. .  Also, the vehicle does not recognize my iPhone 6 anymore. I've read where there might be issues since 3G has been replaced by 5G but no one else I've talked to is having issues with theirs??? Also, GM has a GPS update for about $150 but I can't find out if it covers that issue. Does anyone have helpful suggestions?

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  • 1 month later...

The GPS update is probably a new version of the map data.  I did that a couple of years ago when they had it on sale.  

Since GPS units talk directly to the satellites, changes in cellular to 5G are irrelevant.  This may be different on your cellphone.

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