Control Unit Identification — Part #74970-THR-A12
The power tailgate control unit, made in Japan. This is the component that failed due to water damage from the body seam leak.
Video Walkthrough
Video Coming Soon
A detailed walkthrough showing how to access the tailgate panels, what was discovered, and how easily the panels reassemble — demonstrating that no damage was caused by the inspection.
Photographs
Circuit Board Corrosion — Top View
Extensive green corrosion visible across the PCB. Discoloration patterns indicate repeated water exposure over time — not a single incident.
Water Damage — Close-Up Detail
Dried water stains and corrosion patterns. The staining shows where water pooled and evaporated repeatedly, indicating a slow chronic leak — not a flooding event.
Understanding the Defect
What Happened (In My Opinion)
- 1. Adhesive at body panel seams failed, creating a water entry point
- 2. Water entered during normal driving and rain exposure
- 3. Water accumulated in the tailgate cavity over months or years
- 4. Repeated wet/dry cycles caused the observed rust and corrosion
- 5. Power tailgate control unit eventually failed due to moisture damage
Key Evidence Points
- ✓ Green corrosion indicates prolonged moisture exposure, not a single event
- ✓ Dried water stain rings show pooling and evaporation cycles over time
- ✓ Rust is behind interior panels — not reachable from outside
- ✓ Same pattern documented in 2018–2021 class action lawsuit
- ✓ Vehicle is only 3 years old — premature for this corrosion level
Related: 2018–2021 Honda Odyssey Class Action Lawsuit
A class action lawsuit was filed for 2018–2021 Honda Odyssey models experiencing the same body seam glue failure causing water intrusion. My 2023 model exhibits identical symptoms, suggesting Honda did not fully resolve this manufacturing problem before continuing production.