How to test a DC fan using a battery & a test light Ft. Tool Girl Jade #1455

DC electric motors are used in many components on a modern car, although some of the more obvious applications are for the cooling fan for the radiator & of course the blower motor hiding under the dash... Often it's just a single winding that fails, however, on most occasions the fan will still operate unless it just happens that the armature stops in exactly the 'wrong' place causing an open circuit & preventing the motor to restart. This simple test using a test light and a battery will easily highlight any 'bad' windings or commutator segments. The issue could also be worn out brushes as these usually lose contact with on some parts of the commutator first. Andy Mechanic