Disconnect the negative (-) batttery terminal.

Disconnect the A/C & heater controller connectors (A).

(Refer to Heating, Ventilation And Air Conditioning - "Heater & A/C Control Unit (Manual)")

(Refer to Heating, Ventilation And Air Conditioning - "Heater & A/C Control Unit (FATC)")

Operate switch and check that continuity exists between the terminals.

If there is no continuity, replace the seat heater switch.

Disconnect the negative (-) batttery terminal.

Remove the rear door trim.

(Refer to Body - "Rear Door Trim")

Operate driver seat heater switch and check that continuity exists between the terminals.

If there is no continuity, replace the seat heater switch.