A/C Not Cooling Well at Highway Speed

[edithgrove102]

Hello all!

I have a 2009 Aveo 2LT with a 1.6 LXV engine and automatic 4-speed AISIN transmission.

The A/C cools just fine at city speeds, but at highway speeds on warm days the A/C just barely keeps the passenger compartment cool even when using "MAX."

Anyone else have this problem and what did you do about it?

EDIT: Forgot to mention my car is equipped with option WHB "GM-LAN enhanced electronic speed signal" whatever that is.