LCM Alert Validation

Confidence

Failure Category

Lighting

Subcategory

light failure

Sensor Verdict: The LCM sensor flagged the YELLOW (Left/Road Side Turn) circuit on trailer V560249. Based on the available evidence, the sensor did detect a real lighting defect on this trailer, though the specific faulted circuit identification may be imprecise. The PCT app screenshot (IMG_2245) shows the Brown circuit (Running/Marker lights) as 'Defect/s resolved,' while the Yellow circuit shows 'No defects.' This suggests the root defect was on the Brown/Marker circuit rather than the Yellow/Turn circuit. Confidence is rated at 88% that a genuine defect existed — the sensor was correct in flagging a problem on the trailer, even if the circuit attribution may have been slightly off, which is not uncommon when a marker light on a shared harness run creates bleed-over or cross-circuit anomalies.

Photo Evidence: The photo set is reasonably comprehensive. Photos TC_08201 and TC_08208/TC_08210 show red clearance/marker lights at the rear lower corners of the trailer — TC_08201 shows the driver-side low corner marker illuminated (red, functioning post-repair), while TC_08208 shows what appears to be the same light position with a three-socket housing where at least one socket appears empty or has a degraded bulb, consistent with the reported inoperative light. TC_08200 and TC_08209 show amber mid-trailer side marker lights illuminated (functioning). TC_08207 shows the license plate light functioning. TC_08197 shows the nosebox wiring — it is open and visible, though the wiring appears dense and somewhat disorganized with multiple wire types present. TC_08194 and TC_08198/TC_08199 show the front and rear corner clearance lights. TC_08196 shows the 7-way connector with clean, undamaged pins. TC_08202 shows the rear door area with top clearance lights. Photos TC_08203, TC_08204, TC_08205, and TC_08206 show the rear of the trailer at various stages — rear lights appear to be functioning red brake/tail lamps visible in all frames. The PCT app screenshots (IMG_2245 and IMG_2246) are present and show full circuit verification. However, photos of every individual light in the Yellow turn circuit specifically illuminated are not fully documented — mid-turn and rear turn signals are not individually captured in a lit state.

Vendor Compliance: The vendor (TA) demonstrated generally good compliance with the LCM troubleshooting procedure. The PCT TechAssist app was used, as confirmed by both the technician notes and the app screenshots (IMG_2231, IMG_2245, IMG_2246). All five circuits are shown as 'Verified' in the Sensor Details screen. The nosebox was opened and photographed (TC_08197). The 7-way connector was inspected and terminals tightened (TC_08196). The technician noted checking all lights and functions, used the PCT app to identify and resolve the defect, and provided post-repair verification. The feedback category used ('found defect and resolved issue by replacing light') aligns with the expected 'light failure' category. One gap is the absence of photos showing each turn signal circuit light illuminated individually — the yellow left-turn side markers and rear turn lamps are not fully photo-documented in an illuminated state, which is a minor documentation shortfall.

Repair Summary: The technician replaced the driver-side (road side) low rear corner marker light — identified as a 'DS LOW CORNER REAR MARKER LIGHT INOP' — with a new Mini LED Red Marker (part 33250R, $23.99). A light pigtail was also replaced (R/R LIGHT PIGTAIL) with seal-a-crimp butt connectors used for the splice. The repair correctly addressed a functioning lighting defect on the trailer. The PCT app Job Summary (IMG_2246) confirms 'Light Circuit√' as verified with Brown/Marker Power active at 13.067V. However, the repaired light (red rear marker) is associated with the Brown circuit, not the Yellow (left turn) circuit that generated the original LCM alert. The ATIS Lamp sensor was also noted as 'Not Connected / Unverified' in IMG_2231, which may warrant a separate follow-up.

Key Concerns: The primary concern is the circuit mismatch — the LCM alert was for the YELLOW (Left Turn) circuit, but the repair addressed a Brown circuit (running/marker) lamp. This could indicate the LCM sensor misidentified the circuit, or that the marker light failure created enough of a load anomaly to trigger a false yellow circuit alert. The PCT app confirms no yellow circuit defect was found, and the brown circuit defect was resolved, which supports the theory that the sensor alert was associated with the correct trailer but potentially the wrong circuit color. Additionally, the ATIS Lamp sensor shows as 'Not Connected' in the gateway details (IMG_2231), which is a separate unresolved issue that should be flagged for follow-up. The nosebox wiring (TC_08197) appears heavily populated and somewhat aged — a general wiring inspection may be warranted. No repeat issues or prior work order patterns are visible from this data alone, and the vendor did not attempt to bypass or shortcut the PCT verification process.