I've recently had a bout of interference issues with my GPS unit, a TomTom. I found that if I place it on top of the doghouse, the FM radio will mess it up royally. No doubt about it. I listen to 94.3 regularly here in the Chicago area, and that causes the GPS to lose the signal and/or to drift all over the place-- it's been as much as five miles out from where it really is. Turning off the radio causes the GPS to get it's bearings again and it works without fault as long as the radio is off, or on an AM station.
If I place the GPS on the dash, then the radio doesn't affect it. Problem: Because of the way the dash is shaped, part of the screen is hidden from view unless you really strain to see it.
Before I forget: I drive a '98 Chevy 2500 van, and there is room on top of the ashtray (mounted on the doghouse, and I never use the ashtray) to place the GPS. The radio is the standard AM/FM Delco radio that came from the factory.
If I place the GPS on the dash, then the radio doesn't affect it. Problem: Because of the way the dash is shaped, part of the screen is hidden from view unless you really strain to see it.
Before I forget: I drive a '98 Chevy 2500 van, and there is room on top of the ashtray (mounted on the doghouse, and I never use the ashtray) to place the GPS. The radio is the standard AM/FM Delco radio that came from the factory.