If you mean one on the steering column, it is probably the hazard flasher button. Otherwise it could be anything.
The 1991 Toyota Camry has an alarm system button below the steering column. The ignition must be turned on and the button pressed for 30 seconds to deactivate the alarm.
Below steering column on console panel, above brake pedal
it is on the steering column below the steering wheel
directly below steering column on kick panel (RHD) directly below steering column on kick panel (RHD)
There is a push button that can be pressed up or down (it is rectangular in shape) located below the air vent to the left of the steering column.
It's on the dash to the right of the steering column. Almost directly below where the ignition key goes. It looks like a button you can insert a key into.
On steering column. Remove plastic collar from steering column behind the steering wheel (2 Phillips screws from below). Flasher relay located to the upper right of the column. Pull out away from driver.
On top of the steering column, below the steering wheel.
On steering column directly below steering wheel. Behind a plastic cover.
Below steering column
Below the steering column on the left
Below and to the left of the steering column.