2005 Infiniti FX35 U1000 & U1001 CAN Communication Fault: Water Damage and Fail-Safe Mode Diagnosis

I own a 2005 Infiniti FX35 and am seeking advice on resolving persistent electrical issues after water damage. When I purchased the vehicle four years ago, I noticed water seeping into the cabin following heavy rain. Upon investigation, I discovered that the sunroof gutter connections were blocked, causing water to leak underneath the carpet. While I successfully fixed the leak, the vehicle developed several electrical faults shortly thereafter. Symptoms include: no power to the front wiper motor, fog lights not functioning, both climate control fans running at high speed when the ignition is set to AC (even without starting the engine), headlight dimming malfunction (headlights stay on and the switch has no control), and dashboard warning lights such as ABS, VDC OFF, SLIP, and AWD are illuminated. After scanning with an OBD2 scanner, I received diagnostic codes U1000 and U1001 — CAN Communication Circuit errors. These codes are linked to multiple modules including the Body Control Module (BCM), fog light system, auto headlamp control, and others. The vehicle appears to be in 'Fail-Safe Mode,' as indicated by the failure of several systems. I’ve tried cleaning and retightening all ground connections under the dashboard, following Nissan’s recommended procedures. However, the symptoms persist. Given that water had previously infiltrated beneath the carpet, I’m now wondering whether the root cause is a damaged CANBUS wiring harness or a grounding issue. Should I focus on repairing the CAN network under the carpet, or is it more likely a module-level failure? I’ve also found a workshop manual reference (http://workshop-manuals.com/infiniti/fx...540001.png) that shows symptoms matching my vehicle’s behavior — confirming the fail-safe state. Despite attempts to reset or exit this mode, no improvement has been achieved.