David: I would look for volt. drop path between bat.-remote bat. stud-underhood acc. wiring junction block-ing2 60A maxi-fuse-ign. sw.D2Red-ign. C6 Org to inst. panel fuse box HVAC 10A fuse to C5 BRN. at control head. Bat.+ is at C12 ORN. at HVAC from bat 1 60... Login to read more.