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How to Test a Bad Relay in Your Car

Dan McGovern
Automobile is absolutely necessary for human daily life. So having a general idea of it is very useful when your car has some problems outside. There are a lot of parts on the car. Let’s take a little part of it, that is automotive relay.
You should know common faults of automotive relays including, coil burnt, short circuit, insulation aging, contact ablation, etc.
1) Turn on the ignition switch and hear whether there is a pull-in sound in the control relay or feel the relay with your hands for vibration. If so, it means that the relay is basically in routine use. The failure of the circuit may be caused by other reasons. On the contrary, it means that the relay is faulty.
2) Replace the relay to be tested with an identical working relay. Turn on the switch, and if the electrical equipment is working normally, it can be determined there is a problem with the relay to be tested.
3) Use the multimeter Rx100Ω gear and combine the resistance of each pin of the circuit to analyse. If the conduction and disconnection are normal, it means that there is no problem with the relay, otherwise it means the relay is faulty.
4) Open the relay shell to check whether the contacts are ablated or oxidized. If there are bumps and rust on the contact, it means that the contact is ablated or oxidized and does not work properly.
5) Check whether the coil is ablated or discolored. If the coil is ablated with jelly, the coil is black or has a gluey smell, which means the coil is short-circuited by ablation.
RELAYS are widely used in automotive circuits, such as starting system circuits, wiper circuits, and rear window heating circuits. To get MORE INFO about how to test a relay, you can press the following button.
More Info: Relay Test