F 250 2WD Super Duty V8-7.3L DSL Turbo VIN F (1999)
Horn Relay: Testing and Inspection
Alternative Testing
Terminals
MICRO ISO RELAY (HALF)
Use 73 Digital Multimeter to check for 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 the test. Use two jumper wires to connect relay terminal 1
and terminal 3 directly to the positive battery terminal. Set 73 Digital Multimeter in 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 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.
MINI ISO RELAY (FULL)
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. Using two jumper wires, connect relay
terminals 86 and 20 directly to the positive battery terminal. Set 73 Digital Multimeter in 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 a known good ground. Check for voltage at terminal 87. If battery voltage is not indicated, replace the relay.
