GM Chevrolet Avalanche - Manual (Page 143)

Even when the water management system is working
properly and the cover system is on, there may be some
instances (heavy rains, automated car washes, etc.)
when water may be present in the following areas:
A. Top drain grates
B. Removable front drain grate (Midgate drain gate)
C. Side rail channels and catch cups
D. Front drains
E. Water drainage area (around both sides of the box
and the tailgate side)
F. Rear drains
G. Cargo floor
H. Cargo mat (central area of mat is intended to be dry)
Maintenance and Cleaning
To ensure that the water management system performs
properly, be sure that the midgate, tailgate and cover
system are fully closed and that each element of
the water management system is clean and not blocked
with debris. Follow the instruction given next in this
section for the proper procedures on cleaning each item
of the water management system.
2-73