Horn
Pressa 
on the steering wheel pad
to sound the horn.
See also:
How to Add Automatic Transmission Fluid
Refer to Recommended Fluids and Lubricants on page 11‑12 to determine what kind of transmission fluid to use.
Using a funnel, add fluid down the transmission dipstick tube only after checking t ...
How to Add Coolant to the Radiator
WARNING
An electric engine cooling fan under the hood can start up even when the engine is not running and can cause injury. Keep hands, clothing, and tools away from any underhood electric fan.
WAR ...
Safety
The National Highway Traffic Safety Administration gave the 2007 Yukon a
five-star frontal crash-test rating; it hasn't done a side-impact test as of
this writing. Rollover ratings were listed at ...