Chevrolet 2007 Avalanche Owner's Manual page 186

The areas where water could collect are:
A. Top drain grates
B. Removable front
drain grate
(Midgate
drain gate)
C. Side rail channels
and catch cups
D. Front drains
186
E. Water drainage
area around
both sides of the
box and the
tailgate side
F. Rear drains
G. Cargo floor
H. Cargo mat
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 part 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 part of the water
management system.