guys.. i not sure this is issu or not, it was the aircond vent did not change (outside air flow and inside air circulation). previously i notice that whenever i turn off the aircond it will auto switch to outside air flow (green light). but now it still at inside air circulation (amber/yellow) although sometime i set auto and turn up the temp to HI...

thanks izputra, i also prefer that as my parking lot is near to the disposal area. but it was out of the norm so just worry that it might lead to other problem.