2005, 300 with factory one cd-4speaker sterio, antenna in rear glass. for 2 years on hot days over 100 degrees radio looses reception until it cools down..NOW, on cold overcast days radio loosed reception until the weather clears or warms up. i live in california.. dealer has been no help.. radio unit was checked while acting up and is ok, problem is said to be from radio back.. is there a antenna module or booster in the car that could cause this or what??? any and all help would be appreciated.. has anyone heard of this..