CarTalk.com Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

UnCool At Any Speed

The air conditioner comes on in my 06 Hummer only after the car goes over 40 mph. I checked all the fuses and diods under the hood and nothing seems wrong.

Since your vehicle is the most uncool thing there is, it is only fitting that the A/C keeps the family tradition alive…I hope, for your sake, that the windows still roll down…

Just what were you looking for under the hood? Your most likely problem is a low refrigerant charge.

I’d also ask whether or not you’re confusing the temperature of the air with whether or not the fan is actually blowing it. If your blower fan is not operating, the AC might be cooling, but you won’t get any air flow until the movement of the vehicle forces it through the fresh air intake.