My 2006 Holden Commodore VS6 VE is over heating. The top radiator hose came off. Fixed this. Checked this morning run car was fine. Turned AC unit on and within 5 min it started to over heat. Turned AC unit off and she is running fine again.
I would look to see if your high speed fan is working on the radiator. Or if the fan is working at all when the Air Conditioning is turned on. You may have a bad high speed fan relay.