Component Tests

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:

Half ISO Relay
Use 73 Digital Multimeter to check for continuity between terminal 2 and all other terminals. If resistance is 5 ohms or less between terminal 2 and any other terminal, replace the relay. If resistance is greater than 5 ohms, continue the test. Use two jumper wires to connect relay terminals 1 and 3 directly to the positive battery terminal. Set 73 Digital Multimeter to the volts position and check for voltage at terminal 4. If battery voltage is not indicated, replace the relay. If battery voltage is indicated, connect the third jumper wire to terminal 2 and ground the jumper wire to ground. Check for voltage at terminal 5. If battery voltage is not indicated, replace the relay.







Full ISO Relay
Use 73 Digital Multimeter to check for continuity between terminal 85 and all other terminals. If resistance is 5 ohms or less between terminal 85 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 86 and 30 directly to the positive battery terminal. Set 73 Digital Multimeter to the volts position and check for voltage at terminal 87A. If battery voltage is not indicated, replace the relay. If battery voltage is indicated, connect a third jumper wire to terminal 85 and ground the jumper wire to ground. Check for voltage at terminal 87. If battery voltage is not indicated, replace the relay.