Up-Shift Light (Manual Transmission); Brake System Warning Light - Chevrolet Silverado Classic 2007 Owner's Manual

Readings in the low warning zone may occur
when a large number of electrical accessories
are operating in the vehicle and the engine is
left at an idle for an extended period. This
condition is normal since the charging system
is not able to provide full power at engine idle.
As engine speeds are increased, this condition
should correct itself as higher engine speeds
allow the charging system to create maximum
power.
You can only drive for a short time with the
reading in either warning zone. If you must
drive, turn off all unnecessary accessories.
Readings in either warning zone indicate
a possible problem in the electrical system.
Have the vehicle serviced as soon as possible.
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Up-Shift Light
(Manual Transmission)
It will come on when you should shift to the next
highest gear. It will help the vehicle get the
best fuel economy.

Brake System Warning Light

With the ignition on, the brake system warning
light will flash when you set the parking brake.
The light will flash if the parking brake does
not release fully. If you try to drive with the parking
brake engaged, a chime will sound when the
vehicle speed is greater than 3 mph (5 km/h).
Your vehicle may
have an up-shift light.