The engine may overheat at idle when the AC is on. A new, upgraded fan motor and resistor assembly should be installed.Google+
Car Problem Reports
Ford Crown Victoria Engine May Overheat at Idle With AC On
Ford Crown Victoria Problem
Average Mileage: 160,065 mi (125,000 mi - 215,000 mi)
Visitor, 2007 Ford Crown Victoria, 125,000 mi
The air conditioner tends to stop blowing cold air at idle for more than a few seconds (like at a stop light) and after about 10 minutes of idling the temp gauge goes through the roof. I don't remember hearing the electric cooling fans come on at any time.
2006 Ford Crown Vic Police Package overheats while idling with AC on. When idling with the AC on the temp of the car shoots through the roof and the temp warning light turns on and the AC starts to blow hot air and the car acts as if its going to stall out.
Visitor, 2006 Ford Crown Victoria, 155,000 mi
air conditioner stops blowing cold air at idle. Extended idling the temp gauge goes high and warning triggers.
electric cooling fan is operating. At idle the compressor seems to be kicking in and out, pulling the motor down momentarily.
THE COOLANT FAN MOTOR DO NOT STOP IT WORK ALL THE TIME