OnStar/XM radio interference with GPS?

[spitz31]

I recently bought a 2006 Tahoe that has XM radio and Onstar. I don't use or pay for either service. When I try to use my Tomtom in the Tahoe, I cannot get a signal when the car is on. When i turn the car off, the GPS acquires its signal. Tried a buddy's Garmin and the same problem, no signal when the car is on.

Does anyone know what might be the reason for the GPS not being able to get a signal? Might not be the XM/Onstar, but seem like likely candidates.

[hopeforfish]

I can not use my fuzzbuster and gps at the same time. It seem that my garmin atracts a lot of interference.

[jerkbait]

I use my H2O in my truck and I have both XM and onstar. I only subscribe to XM though. My GPS works just fine.

[Skeeter21i]

I have both XM and Onstar and haven't had any problems with GPS not working properly. Is the key in the "off" position when your GPS starts working or does just the engine need to be off for it to work?

[spitz31]

I have the GPS on with signal and the car off. When I turn the key to the on position it loses signal. I guess the engine running doesn't have anything to do with it.