4-36. Marker Clearance Light (Including M129A4 With LED Lighting System)
This task covers:
General mechanic's tool kit (item 01, Appendix B)
Power source disconnected.
Dishwashing, soap (item 17, Appendix E)
Rags (item 14, Appendix E)
All semitrailer running lights are controlled by the electrical system of the towing vehicle. A master
switch on the towing vehicle controls the service and blackout modes of operation of the lights. Place
this switch in the proper position prior to testing the lamps after installation. Marker clearance light
(LED) assemblies will not light if towing vehicle switch is in the OFF position.
1. Remove two screws (1) from marker clearance light (LED) assembly (2).
2. Remove wiring harness plug (3) from back of marker clearance light (LED) assembly (2).
3. Remove marker clearance light (LED) assembly (2).
b. Cleaning and Inspection
Do not use dry cleaning solvent. It will damage the body of the light.
1. Clean light, using clean water and soap (item 17, Appendix E) solution.
Dry thoroughly with clean rags (item 14, Appendix E).
2. Check wiring for damaged or worn insulation.
3. Inspect body for cracks, dents, warpage and cracked
or broken lens.
4. Make sure all parts are in good condition and will make
good electrical contact and watertight connections.
5. Replace light if defective.
1. Ensure wiring harness grounding screw (4) is properly installed and tightened.
2. Install wiring harness plug (3) in the back of marker clearance light (LED) assembly (2).
3. Install two screws (1) in marker clearance light (LED) assembly (2).
4. Test light by turning on switch in towing vehicle.
Follow-on maintenance: None