Homelink system fading
The Homelink system (called Universal Home Remote System in my owner's manual) in my '09 Acadia is fading. I can open the garage door with it while my vehicle is inside the garage, but after I've backed out, the system won't close the garage door. When I return home, it won't open the garage door, but after I've driven into the garage I can close the garage door with the system. How can that be? While inside the garage, the vehicle is directly beneath the garage door opener. When in the driveway, it's within maybe a dozen feet. The system surely should work within that range -- until recently it worked much farther away than that. What part of the system is failing, and what's the fix?
2009 Acadia SLT-2 AWD, 8 pass., Red Jewel Tintcoat, Light Titanium, Bose radio/NAV. Ordered on 8/29/08; delivered on 10/10/08.