Turn Signals When Towing a Trailer
The turn signal indicators on the instrument panel flash whenever signaling a turn or lane change.
Properly hooked up, the trailer lamps also flash, telling other drivers the vehicle is turning, changing lanes or stopping.
When towing a trailer, the arrows on the instrument panel flash for turns even if the bulbs on the trailer are burned out. Check occasionally to be sure the trailer bulbs are still working.
See also:
Engine Oil
For diesel engine vehicles, see “Engine Oil” in the Duramax Diesel Supplement.
To ensure proper engine performance and long life, careful attention must be paid to engine oil.
Following these si ...
Trailer Gain and Output
On vehicles with the Integrated Trailer Brake Control (ITBC) system, the trailer brake display appears in the DIC. Press the trip odometer reset stem until TRAILER GAIN and OUTPUT display.
TRAILER GA ...
Selecting the Right Engine Oil
Selecting the right engine oil depends on both the proper oil specification and
viscosity grade. See Recommended Fluids and Lubricants on page 11‑12.
Specification
Use and ask for licensed e ...





