How do you test a blower motor switch?

Test the switch. Plug the connector back in to the blower motor, and then trace the wire harness back to the connector closest to the blower motor switch, usually located under the dash. Disconnect the connector and set the multimeter to ohms.

How do I know if my blower motor switch is bad?

Another symptom of a bad or failing blower motor switch is a switch that is stuck, or frequently gets stuck. If the switch or any of its contacts becomes damaged, this may cause the switch to jam, or get stuck when you trying to change the setting.

How do you test a blower motor resistor with a multimeter?

Place one lead of the Ohmmeter on terminal 1 of the resistor. Place the other lead on terminal 2 and check against specifications. If this circuit is open, showing infinity on the Ohmmeter, the blower resistor must be replaced. Move the lead from terminal 2 to terminal 3 and check this reading against specifications.

What happens when blower motor relay goes bad?

If the blower motor relay develops any sort of problem that hinders its ability to properly limit and distribute power, it may cause the blower motor fuse to blow. Any sort of electrical spikes or excessive current from a bad relay will blow the fuse and cut power in order to protect the system.

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What can cause a blower motor to stop working?

In most cases, a blower motor resistor fails due to corrosion or overheating. Sometimes, the mechanical resistance to the motor rotation causes an excessive electric current that can overheat and prematurely damage the blower motor resistor.

How do you test a blower motor relay?

Connect a test light or multimeter to the ground (black lead). Turn the ignition key to the on position (engine off), and remove the relay. Using the probe, test all terminal sockets in the relay connector. Two of the four should have power.