GMC CHEVROLET Silverado 1500 2021 Owner's Manual page 398

Keyless Access, keep the RKE transmitter
outside of the vehicle and manually lock
the doors. Access the vehicle by using
the key in the door lock. See Door Locks
0 21.
Disconnecting the Towed Vehicle
Before disconnecting from the tow vehicle:
1. Park on a level surface. Secure the
vehicle with wheel blocks.
2. Re-connect the negative ( ) battery. See
Battery - North America 0 342.
3. Turn on the ignition with the engine off.
For vehicles with a key, turn the ignition
to ON/RUN with the engine off. If the
vehicle is equipped with Keyless Access,
with your foot off the brake pedal, press
and hold ENGINE START/STOP for
five seconds until the green light comes
on in the button. See Ignition Positions
(Keyless Access) 0 230 or
Ignition Positions (Key Access) 0 229.
4. Set the parking brake. See Electric
Parking Brake 0 246.
5. Disconnect from the tow vehicle.
6. Shift the transmission to N (Neutral).
7. Shift the transfer case to 2 (Two-Wheel
Drive High). When the shift to 2
(Two-Wheel Drive High) is complete, the
light in the instrument cluster will stop
flashing and stay lit. See
Four-Wheel-Drive Light 0 118.
8. Start the engine. Check that the vehicle
is in 2 (Two-Wheel Drive High) by
starting the engine and shifting the
transmission to D (Drive) and then to
R (Reverse). There should be movement
of the vehicle while shifting.
9. Shift the transmission to P (Park) and
turn off the ignition.
10. Release the parking brake and remove
the wheel blocks.
11. Reset any lost presets.
The outside temperature display will
default to 0 °C (32 °F) but will reset with
normal usage.
Vehicle Care
Dolly Towing
397