When all lights in your 2020 Subaru Ascent flicker erratically after flood exposure, you're seeing the effects of water in the electrical system causing intermittent connections and communication failures. This symptom indicates widespread electrical issues requiring professional attention.
What Causes Post-Flood Flickering
Water in the main electrical distribution points - body control module, junction boxes, or ground connections - creates unstable power delivery. As water evaporates, connections make and break randomly. Multiple systems share power paths, so one water intrusion point affects many circuits.
Body Control Module Issues
The body control module (BCM) controls most lighting functions. If water reached the BCM, its operation becomes erratic. Flickering lights often indicate BCM communication problems with other modules - code U0001 confirms high-speed CAN bus issues.
Ground Connection Problems
Vehicle grounds are often located in floor areas that flood first. Corroded grounds create resistance that varies as connections make and break, causing flickering. Multiple systems share grounds, explaining why many lights flicker together.
The Corrosion Factor
Even after water dries, corrosion continues developing on copper connections. Flickering may actually worsen over days or weeks after the flood as corrosion builds. Early intervention - cleaning and treating connections - can prevent this progression.