Title
Troubleshooting an L-861(L) Medium Intensity Elevated Edge Light
URL Name
Troubleshooting-an-L-861-L-Medium-Intensity-Elevated-Edge-Light
Summary
This article covers how to go about troubleshooting an L861 LEDMedium Intensity Elevated Edge Light
Owner
Mike S

Question

What corrective action is taken if the L-861(L) Medium Intensity Elevated Edge Light does not illuminate?

How do you troubleshoot no light output on the L-861(L) Medium Intensity Elevated Edge Light?

What steps address intermittent operation of the L-861(L) Medium Intensity Elevated Edge Light?

Why might the L-861(L) Medium Intensity Elevated Edge Light show reduced intensity and what is the fix?

What causes the L-861(L) Medium Intensity Elevated Edge Light to operate at incorrect intensity steps?

How is a failed light engine diagnosed in the L-861(L) Medium Intensity Elevated Edge Light ?

What troubleshooting step applies if the L-861(L) Medium Intensity Elevated Edge Light does not respond to dimming?

What should be checked if the arctic kit heater does not function on the L-861(L) Medium Intensity Elevated Edge Light?

What is the first action when troubleshooting any L-861(L) Medium Intensity Elevated Edge Light malfunction?

When should technical support be contacted for the L-861(L) Medium Intensity Elevated Edge Light?

What information should be provided when calling support for L-861(L) Medium Intensity Elevated Edge Light?

Where is the troubleshooting table located in the L-861(L) Medium Intensity Elevated Edge Light owner's manual?

Content

Overview

This article walks you though how to troubleshoot an LED Medium Intensity Light. You can also view a more guided flow style walkthrough by using the link below. Select L861 from the product guides dropdown box.

Guided Product Troubleshooting

Identify the Symptoms

  • Record the symptoms.

    • Does the fixture illuminate?
    • Is the light dim (noticeably weaker than normal), flickering/intermittent, or going on and off randomly?
    • Does it happen only on one intensity or all?
    • Was there any environmental factors?
    • Are there any signs of water intrusion?

General Troubleshooting Notes

Always first determine if the fixture is getting the correct input power, if correct then de-energize before performing any further troubleshooting or replacement. Use insulated tools and follow lockout/tagout procedures. Record fixture catalogue number, serial number, position in the circuit and observed symptoms.

See Verify Isolation Transformer Output/Fixture Input Current for details on how to complete that check 

Test the light engine

The easiest way to isolate the problem is to open the fixture and perform a diode test after de-energizing to determine if the light engine is faulty. If there are any signs of water intrusion replace the head in its entirety.

See Perform a Diode Test on the L861 LED Light Engine  for details on how to complete that check 

If the diode test passes then replace the light engine, if the diode test fails replace the driver board. Refer to the table below to see various symptoms and their possible cause and solution. Swap testing from a known good fixture is a great way to determine exactly what has failed.

Symptom

Possible Cause

Corrective Action

No illumination

No power to fixture

Failed light engine

Failed Driver

Failed isolation transformer

Verify Isolation Transformer Output/Fixture Input Current

Replace the Light Engine

Replace the driver board

Replace transformer

Intermittent operation 

Loose connections

Failing parts

 

Circuit degradation

 

Inspect and tighten all connections

Swap test components
Replace the Light Engine
Replace the driver board

Megger test the circuit

 

Reduced intensity

Dirty or damaged lens

Failing parts

Failed or undersized transformer

Clean or replace lens

Swap test components

Test/Check the isolation transformer. Replace if necessary.


 
Airport Lighting Company | Troubleshooting Instruction 
Internal Notes

Digital Engagement Response

Article Created Date
2/25/2026, 4:00 AM
Publication Status
Published
Created Date
3/13/2026, 6:29 PM
Article Total View Count
72
Created By
Mike S, 3/13/2026, 6:29 PM
Archived Date
Last Modified Date
3/13/2026, 6:30 PM
Last Modified By
Mike S, 3/13/2026, 6:30 PM
Last Published Date
3/13/2026, 6:30 PM

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