THECARRIERSTANDARD.COM
TRAILER LIGHT FAULT-FINDING SHEET
For stationary inspection only. Not a certification of electrical safety.

Date: __________  Tow vehicle year/make/model: __________________________
Trailer type: __________________  Connector: [ ] 4-way [ ] 7-way RV
[ ] Other / unknown: __________________  Person checking: _______________

1) IDENTIFY THE FAULT (do not guess a cause)
                 Before repair      After repair
Running / tail   PASS FAIL N/T      PASS FAIL N/T
Left turn        PASS FAIL N/T      PASS FAIL N/T
Right turn       PASS FAIL N/T      PASS FAIL N/T
Brake lights     PASS FAIL N/T      PASS FAIL N/T
Hazards          PASS FAIL N/T      PASS FAIL N/T
Marker / plate   PASS FAIL N/T      PASS FAIL N/T
N/T = not tested. Mark every applicable installed lamp.

2) PLUG + HARNESS VISUAL INSPECTION (power off)
[ ] Plug seats securely   [ ] No bent/burned/corroded pins
[ ] No loose/pinched/exposed wiring near hitch or frame
[ ] Main trailer ground appears secure and undamaged
[ ] Individual lamp grounds inspected as applicable
Findings: ________________________________________________________________

3) ISOLATE VEHICLE FROM TRAILER
Vehicle socket tested with compatible device? YES / NO
Running lights: PASS / FAIL / NOT TESTED
Left stop/turn:  PASS / FAIL / NOT TESTED
Right stop/turn: PASS / FAIL / NOT TESTED
Ground verified appropriately? YES / NO / NOT TESTED
Vehicle issue suspected? __________ Trailer issue suspected? __________
Note: a basic indicator tester does not prove performance under load.

4) RECORD THE FIRST FAILED CHECK
What was actually observed? ______________________________________________
Location of suspected issue: ______________________________________________
Action taken and component checked: _______________________________________
Who verified repair? ______________________________________________________

5) RELEASE CHECK BEFORE TOWING
[ ] All required road-light functions now pass consistently
[ ] Plug latched, wiring secured with turn clearance and no drag hazards
[ ] No warm wiring, repeat blown fuse or unresolved electrical faults
[ ] Trailer brake system, if installed, checked separately
[ ] If uncertain: qualified trailer service / auto electrician consulted

STOP: DO NOT TOW ON PUBLIC ROADS WITH REQUIRED LIGHTS MALFUNCTIONING.
This record is a diagnostic aid, not a legal inspection or repair warranty.
Sources: CURT trailer wiring guide; etrailer wiring and ground troubleshooting.