GMC 2002 Sierra - Manual (Page 323)

4-94
Instrument Panel Jumper Wiring Harness
This harness is included with the heavy - duty and
camper/fifth - wheel trailer wiring packages. The harness
is for an electric trailer brake controller and includes a
trailer battery feed fuse. This harness and fuse should be
installed by your dealer or a qualified service center.
Four Wire Trailer Harness Adapter
If you need to tow a light - duty trailer with a standard
four - way round pin connector, an adapter connector is
included with your vehicle.
Connect the adapter with
the tab (arrow) pointing
towards the top. The cap
on the wiring harness will
lock onto the tab (arrow)
and help hold the adapter
in place.