Hi all,
got a new weirdness with my '05 Impala... been using the "floor" setting a lot on the HVAC because it's finally somewhat cold here, so I like to pump the heat to the floor to warm the cabin without frying my face off. I have noticed mileage falling off but I assumed it was due to winter gas, but today I was sitting at a light and was thinking the engine was sounding awful loud and trashy. then the noise quit. sure enough, the A/C was cycling. I determined that it is cycling on the "floor" setting and everything clockwise from there on the control (floor/defrost mix, and full defrost.) I expected it to run on defrost but it seems odd that A/C should be engaged when only the floor vents are selected. Is this an issue or is it just the way GM designed it to work?
thanks,
nate