The steering wheel switches can be used to operate a connected cellular phone.
Operating a telephone using the steering wheel switches
On hook switch

Bluetooth® phone
message function
Bluetooth® phone
settingsDriver side seat belt buckle switch circuit malfunction
Description
The driver side seat belt buckle switch circuit consists of the center airbag
sensor and the front seat inner
belt lh.
Dtc b1655/37 is recorded when a malfunction is detected in the driver side seat
belt buckle switch circuit.
Wiring diagram
Inspection procedure
...
If a warning light turns on or
a warning buzzer sounds
Calmly perform the following actions if any of the warning
lights comes on or flashes. If a light comes on or flashes, but
then goes off, this does not necessarily indicate a malfunction
in the system. However, if this continues to occur, have
the vehicle inspected by your Toyota dealer.
Actions to ...
Door control receiver
Components
Removal
Remove rear door scuff plate rh
Using a screwdriver, detach the 9 claws.
Hint:
Tape the screwdriver tip before use.
Using a clip remover, detach the 2 clips and remove
the garnish.
Remove rear door opening trim
weatherstrip rh
...