From the day I bought my wonderful car (which was in the 2014 Macy's Thanksgiving Day Parade), there is a loud resonation/vibration emanating from the glove box area in the 20 to 30 mph range and the 40 to 50 mph range. The only way to get it to stop is to increase speed slightly. Spent 30 minutes driving the mechanic around today, we can't figure out what is causing it. He went under the hood, tightened all the cables in the engine area behind the glove box area. It's driving me insane.

Update from Aug 5, 2015: It makes the noise at both idle and 1250 rpms.

Update from Dec 30, 2015: It's Fixed!!! My trusty local mechanic found it, a loose heater cable under the dash. Haven't heard the noise since. Now on to the strange "jingling" noise I hear from the rear end when I go over a bump.

2015 NEW YUKON DENALI has an intermittent rattle/clicking noise coming from the left (drivers side) dashboard area. I have attempted to locate the rattle and cannot pinpoint it's origin. I thought it was the vent, or perhaps the hood release cable, or the e-brake cable/pedal. I have re-adjusted the pedals, the steering column height but nothing solves the problem. It does not happen when the car is cold, but comes/goes intermittently when the car warms-up. I have a feeling that it may be something to do with the "blending" of the hot and cold air when the climate control system is on, but changing the air temp through the vents or re-directing the air (up/down etc.) does not solve the problem. It's annoying. I am afraid that the dealership will just tell me that they cannot duplicate the problem and send me on my way. If anyone else has been able to figure out the source of this rattle, please share your findings. Thank you.