Simple method for judging the working performance of relay
Turn on the ignition switch, and then use your ears or stethoscope to listen to whether there is a sound in the control latching relay manufacturers, or feel whether the relay is vibrating with your hands. If there is, the relay is basically working normally, and the electrical appliance is not working due to other reasons ; Otherwise, it means that the relay works abnormally.
You can also unplug the relay for testing. For example, if the air conditioner compressor does not work, you can start the engine, and then turn on the blower switch and the air conditioner switch. Then unplug the connector of the air conditioner compressor relay to judge. If the sound of the relay can be heard, and the engine speed drops significantly when the relay is unplugged, and the engine speed increases when the relay is inserted, it means that the air conditioner compressor relay and its control circuit are normal.
Regarding the location of the relay, all relays and fuses marked with a dash on the schematic circuit diagram are generally arranged in the central power distribution box.
(2) Common faults of relays Common fault phenomena of relays include: coil burnout, short circuit between turns (insulation aging), contact ablation, thermal decay, and the inability to adjust the initial operating current.
① The relay coil is burned out. In order to prevent this from happening, when repairing, maintaining and welding, if the temperature may exceed 80°C, the temperature-sensitive relay and electronic control unit should be removed.
② Contact ablation. For example, the relay of the air conditioner condenser fan of the Jinbei Hiace car (using the 491Q-ME engine) is just below the glass cleaning spray pipe. If the spray pipe ruptures, the cleaning fluid will leak to the relay, making the relay normally open. The contact is rusty and cannot be disconnected, which will cause the failure of the air conditioner condenser fan to run constantly. Therefore, water should be strictly prevented from entering the relay.
(3) Try to reduce the contact resistance of the relay contacts