NHTSA Complaint #11562794 — 2015 GMC TERRAIN

The blower fan for heat In my vehicle was replaced in October 2022, recently the Defroster will not engage and it is vital to winter driving. The mechanism that switches between which vent to blow out air was replaced and the Defroster will still not engage, rather it comes out of the heat and face vents. Shortly after the Defroster stopped engaging, the rpms will start fluctuating from 2 suddenly up to 6-8 without warning or acceleration then go back down and back up as if it's chugging along. Even when applying the brakes, this will continue to happen and there's concern for Rear-ending or crashing when this happens. When driving home 2 nights ago the county police pulled my vehicle over due to burnt out headlight, which was replaced less than 6 months ago. Took the car in to get bulb replaced today and multiple bulbs later, the light is not fixed and it was said to be electrical and need to go to another shop. Beginning to wonder if this is all a bigger problem about to happen with engine/ powertrain.. with commute to work in the dark and electrical problem in the headlight randomly and the acceleration issues there is definitely a concern for safety.