Main Relay (Computer/Fuel System): Testing and Inspection

Terminal # 30 is usually connected to battery voltage and can be switched or B+ at all times.

Terminal # 87A is connected to terminal # 30 in the de-energized position .

Terminal # 87 is connected to terminal # 30 in the energized position which supplies battery voltage to the operated device.

Terminal # 86 is connected to a switched power source.

Terminal # 85 is connected to the electromagnet and is usually grounded by a switch or ECU.

1. A relay in the de-energized position should have continuity between terminal # 87A and terminal # 30.
2. Resistance value between terminals # 85 & # 86 (electromagnet) is 75 ± 5 ohms for resister relays and 86 ± 5 ohms for diode relays.

Not all relays have battery voltage connected to terminal # 30. Some may have battery voltage connected to terminals # 87 or # 87A.