Here is a video on removing the front hump on the battery pack. AC drain without extension basically dumps right behind the hump. Can see its all sealant + rivots(?) fastners. Fuse door is also just to the passenger side.
Anyway, ample weak points and I think the design didn't account for gravity assisted moisture pools constantly attacking the seal seams. Properly overlapped case lips would have helped. Need solution to better seal the fastener opening. And drainage paths (starting with getting AC runoff out of this area) and routing for any moisture that runs into this area. Windshield runoff and wheel liner intrusions looks like can dump in here as well. The entire firewall/bulkhead area can use a large water barrier + runoff channels covering from windshield to beyond the lowest point on the battery pack extending all the way to the sides. Not an easy mod.. So just chase what statistically has leaked.
Anyway, ample weak points and I think the design didn't account for gravity assisted moisture pools constantly attacking the seal seams. Properly overlapped case lips would have helped. Need solution to better seal the fastener opening. And drainage paths (starting with getting AC runoff out of this area) and routing for any moisture that runs into this area. Windshield runoff and wheel liner intrusions looks like can dump in here as well. The entire firewall/bulkhead area can use a large water barrier + runoff channels covering from windshield to beyond the lowest point on the battery pack extending all the way to the sides. Not an easy mod.. So just chase what statistically has leaked.