Econoline E550 V8-7.3L DSL Turbo VIN F (2002)
Trailer Lamps: Component Tests and General Diagnostics
Mini ISO Relay
Using 73 Digital Multimeter, check for the continuity between Terminal 85 and all other terminals. If the resistance is 5 ohms or less between Terminal
85 and any other terminal, install a new relay. If the resistance is greater than 5 ohms, continue with the test. Using two jumper wires, connect relay
Terminals 86 and 30 directly to the positive battery terminal. Using 73 Digital Multimeter set in the volts position, check for voltage at Terminal 87A. If
battery voltage is not indicated, install a new relay. If battery voltage is indicated, connect a third jumper wire to Terminal 85 and ground the jumper
wire to a known good ground. Check for voltage at Terminal 87. If battery voltage is not indicated, install a new relay.
Micro ISO Relay
Terminals
Using 73 Digital Multimeter, 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, install a new relay. If the resistance is greater than 5 ohms, continue with the test. Using two jumper wires, connect relay
Terminals 1 and 3 directly to the positive battery terminal. Using 73 Digital Multimeter set in the volts position, check for voltage at Terminal 4. If
battery voltage is not indicated, install a new 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, install a new relay.