Horn
Pressa 
on the steering wheel pad
to sound the horn.
See also:
Event Data Recorders
This vehicle has an Event Data Recorder (EDR). The main purpose of an EDR is to record, in certain crash or near crash-like situations, such as an airbag deployment or hitting a road obstacle, data th ...
Customer Assistance Offices (U.S. and Canada)
GMC encourages customers to call the toll-free number for assistance.
However, if a customer wishes to write or e-mail GMC, the letter should be addressed to:
United States
GMC Customer Assistance ...
Interior
Base-model SL G1500 vans have vinyl high-back front buckets and a pair of
rear bench seats for eight-passenger capacity. A dozen people fit into the
G2500/3500 vans, seated on twin three-passenger ...