utmikeg

Hello Everyone, It looks like MWWEISS was correct. I got my truck back on Friday and the dealership discovered it was indeed the antenna. My service agent said there's now a bulletin in GM's system about this issue.They are issuing new antennas to solve the problem. They didn't have the new antenna is stock so they left the old one on so I could get radio reception. I tested the antenna on the way home and stopped half-way there to remove it. The whistle was there with it and gone without it. Thanks for everyone posting their experiences on this forum. It's helpful to have other owners share and offer help. Thanks, Mike

Thanks for the tip MWWEIS. I will see what the dealer comes back with. Coincidentally, because the factory antenna hit my garage door, I replaced it with a shorter version the day after I bought it. I still had the whistling with the shorter antenna. If it comes back with the sound, I will remove the antenna completely and test it. It may require a different antenna altogether. After reading this thread it seems there are no consistent resolutions to this whistling issue.

Thanks SMKN LS1. I drive the 2500 High Country. My noise is the same as the video and happens anywhere around 65-75 MPH. As I mentioned before, my truck is at the dealer so we'll see what they come back with. Thanks for the input.

Sorry for the confusion everyone. I was referring to you SMKN LS1. Thanks for the update. When you say center marker light, are you referring to the optional roof lights? Googling this doesn't bring a very clear answer to what this is. My truck doesn't have roof lights. My wife and I did the same troubleshooting you did and my "whistling" appears to be coming solely from the windshield passenger side only. I even let my wife drive and I sat in the passenger seat. I observed it coming form the passenger side as well. It's very difficult to isolate exactly where it's coming from which makes this so difficult to pin down. SMKN LS1, did your dealer replace the entire windshield as well and the whistle is now gone?

Enthusiast, can you confirm your whistling issue has been resolved? I just sent my truck into the shop this morning for the second time trying to fix the issue. They tried to tell me it was the mirrors. Even folded in it makes that noise. My noise seems to be coming from the front passenger windshield area.