I installed a Bugflector II on my 2003 and immediately began experiancing what sounded like static on the radio. It got worse as the speed increased and was affected by cross winds and passing vehicles.
Taking the deflector off eliminated the "static"
My GM dealership could offer no suggestions, so I tracked down the number for Bugflector's customer service and explained the symptoms to them. The rep I spoke to did not know an answer nor had he heard of the problem.
He did refer me to one of their engineers and he knew exactly what I was talking about. He says that GM had come out with an elaborate fix (this was late 2002) but recommended that I fix it myself.
The turbulence created by the deflector was getting under the rubber trim between the glass and the frame on the verticle window posts and the rubber was snapping up and down on the glass. He said to glue the rubber down, suggesting RTV sealant.
I masked off the glass and rubber, pulled the flap of rubber back a bit and worked RTV sealant back under the rubber. Cleaned up my mess, removed the masking tape and as a precaution, taped down the rubber overnight.
This was over a year ago and I have not had the problem to return
Now, if I can just stop the mirrors from wiggling
myoungcc
MSgt, USAF (Ret)
2003 Silverado 1500 LT
Extended Cab, 8 foot bed