LCM Alert Validation

Confidence

Failure Category

Lighting

Subcategory

Lighting - Failed Light

Sensor Verdict: The LCM RED (Brake) circuit alert on trailer V564061 is assessed as a confirmed defect with high confidence (92%). The technician's hands-on testing corroborated the alert: the Grote third/center brake lamp had voltage present at its pigtail but was completely non-functional, representing a lamp failure on the brake/stop light circuit. The two outboard brake lamps on the right and left sides tested operational. The additional finding of all seven Smart 7-way nosebox terminal nuts being loose further supports a real electrical fault condition that would have degraded circuit integrity and likely triggered or worsened the LCM alert.

Photo Evidence: The submitted photos provide a reasonable but incomplete documentation package. Photos TC_04024 through TC_04033 show the rear of the trailer (AZNG V564061, Idaho plate TL9815) with rear tail lamps illuminated — notably, TC_04030 shows one lamp lit and one appearing dim/partially lit on the right corner, while TC_04033 shows both rear lamps illuminated after repair. TC_04028 shows the top rear marker/identification lights illuminated. TC_04040 provides a clear nosebox (Smart 7-way) photo showing a dense, aged wiring harness with multiple conductors — this is a key diagnostic photo. TC_04041 shows a multimeter reading of 13.13V at the light socket, confirming power present at the Grote lamp location. TC_04042 shows two marker lamp housings removed from the trailer side, appearing damaged/deteriorated. TC_04043 and TC_04047 show amber side marker lamps illuminated (one oval Truck-Lite style, one 6-LED bar style). TC_04044 shows a close-up of a red rear lamp fully illuminated. TC_04050 shows an amber marker lamp detached and lit on the trailer underside area. TC_04052 (dated May 1) shows a Klein Tools multimeter reading approximately 3.98V — this low voltage reading may indicate a test on a different circuit or at a bad connection point. TC_04054 shows both rear corner lamps illuminated on the completed repair date. The TechAssist app screenshots (IMG_4551, IMG_4552) show sensor V564061 paired but all five circuits listed as 'Not verified' / 'No data,' with a 'Backup battery is low' warning on IMG_4552. Critically, no final screenshot showing all circuits verified green was provided, which is a documentation gap.

Vendor Compliance: The vendor (TA) partially followed the LCM troubleshooting procedure. The TechAssist app was used and the sensor was confirmed paired (V564061). The technician photographed individual lamps illuminated and captured a nosebox photo. However, the final TechAssist completion screenshot showing all five circuits with a green 'Verified' status was not provided — the two app screenshots submitted both show 'Not verified / No data' for all circuits, with a low battery warning that may have prevented completion of the digital verification step. The vendor did not explicitly categorize the failure using the prescribed feedback categories in their notes, though 'light failure' is clearly implied. The troubleshooting was substantive and thorough in physical terms but falls short of full procedural compliance due to the missing verified PCT completion screenshot.

Repair Summary: The primary repair was replacement of the Grote third/center brake lamp (RED circuit) with a new Grote unit, secured with new 1/4" aluminum/steel rivets. The right tail lamp was also re-secured with rivets (likely the one showing as partially lit in pre-repair photos). All seven Smart 7-way nosebox terminal nuts were found loose and tightened — this is a notable secondary finding that could independently cause LCM false positives or intermittent alerts. Additionally, two mid-trailer amber marker/clearance lamps were replaced (R&R qty 2), and an Amazon PCT sensor activation was performed. Grote is a compliant brand. Labor charges appear reasonable for the scope of work described across two visits.

Key Concerns: The most significant documentation concern is the absence of a final TechAssist 'Verified' screenshot for all five circuits — the submitted app screenshots show no data and a low battery warning, suggesting the digital verification step was either not completed or not captured. The 3.98V multimeter reading in TC_04052 is unusual and unexplained in the notes (normal trailer voltage should be ~12-13V); this could indicate a bad ground or partial circuit issue that may need follow-up. The work order spans two days and required parts sourcing, which is acceptable, but the multi-visit nature and the loose nosebox nuts across all seven circuits suggest this trailer may have chronic wiring maintenance issues warranting a broader inspection. The marker lamp replacements (amber circuit) were performed alongside the RED circuit repair — these are captured in line items but represent scope beyond the original LCM alert, which is appropriate given the findings.