Component Tests and General Diagnostics

Testing an ISO relay can be accomplished through the use of three No.10 (or larger gauge) jumper wires and 73 Digital Multimeter. Remove the relay to be tested from the power distribution box, fuse junction panel or individual connector.

Terminals:

Component Testing Procedure:

Schematic:

Micro ISO Relay
Use the multimeter to check for the continuity between terminal 2 and all other terminals. If the resistance is 5 ohms or less between terminal 2 and any other terminal, replace the relay. If resistance is greater than 5 ohms, continue with the test. Use two jumper wires to connect relay terminals 1 and 3 directly to the positive battery terminal. Use the multimeter set in the volts position to check for voltage at terminal 4. If battery voltage is not indicated, replace the relay. If battery voltage is indicated, connect a third jumper wire to terminal 2 and ground the jumper wire to a known good ground. Check for voltage at terminal 5. If battery voltage is not indicated, replace the relay.