Purpose

Swap the affected airfield fixture with one that is known to be working and installed on the same circuit.
This helps determine whether the problem lies in the fixture or in the field wiring / transformer at its original location.

Procedure

Deenergize the CCR
Disconnect the pigtail of the suspect fixture from its isolation transformer.
Mount the suspect fixture in the working location without making any internal changes.
Connect it to the isolation transformer at the working location.
Ensure all connections are secure, and strain relief is properly seated.

Restore Power and Observe

Re-energize the CCR and verify that the circuit is powered.
Step through the intensity levels to confirm the fixture responds correctly.
Observe the fixture for steady illumination and proper brightness.

Interpret Results

If the light functions normally in the new position:
- The issue likely lies in the original location’s transformer, wiring, or connector.
If the light still does not power on:
- The fault is likely internal to the fixture, and further component-level diagnostics 

Safety Reminder

Always maintain safe working conditions by using appropriate personal protective equipment (PPE) where necessary.
Turn off power at the Constant Current Regulator (CCR) and apply lockout/tagout before disconnecting or relocating any fixture.
Only qualified service personnel should perform fixture relocation on airfield lighting circuits.
Verify absence of hazardous voltage before handling pigtail connections or isolation transformers.

Airport Lighting Company | Troubleshooting Instruction