How to test a radiator fan on 2005 PT Cruiser? More info, the ac seems to work, but poorly at low RPMs, like when at stop. Local mechanic said the fan wasn't coming on even at 1500 rpms. I swapped the relays around, so unlikely to be that. I probably need new fan assy, but would like to be sure first.

If the car is warmed up and you turn the AC on the fan should turn on. If you have two both should turn on. If your looking at a scanner then the scanner has a functional test to see if the computer can be triggered to turn the fan on. This test confirms the computer is not the probem if voltage is detected at the fan when commanded. When you turn the AC on you should hear and feel a click at the AC relay. When the computer turns the fan on when at 222 degrees or so the fan relay should click and then the fan will turn on if its ok.

To test the fan you need to unplug it and run your own power and ground to it useing jumper wires,if it works then it works,don't worry about hooking it up backwards it will either **** or blow but it will turn if it's good.Get your a/c coolant topped up if your haveing a/c problems at idle.