Set the multimeter to continuity mode or the lowest ohms range
Identify the relay coil terminals using the relay diagram or pinout
Measure resistance across the coil terminals
Check that the coil resistance is neither open nor shorted
Identify the common, normally open, and normally closed contacts
Measure resistance between common and normally closed with the relay unpowered
Measure resistance between common and normally open with the relay unpowered
Apply the rated voltage to the coil terminals
Listen for a click when the relay energizes
Measure resistance between common and normally open with the relay powered
Measure resistance between common and normally closed with the relay powered
Confirm the contact changes state when the coil is energized
Check for unstable readings or intermittent contact movement
Replace the relay if the coil is open, shorted, or the contacts do not switch properly