F 450 2WD Super Duty V10-6.8L VIN S (1999)
S4
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
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