Hazard Warning Switch
WARNING: This page is about a different car, the 2001 Lexus LX 470. However, it is still accessible from the selected car via links, so may be relevant.
- Ensure flasher is okay. Remove A/C-heater control assembly. See REMOVAL & INSTALLATION in appropriate AUTOMATIC A/C-HEATER SYSTEMS article in AIR CONDITIONING & HEATING.
- Using a 12-volt source, apply battery positive voltage to A/C (center) ECU terminal No. 12, and battery negative to terminal No. 22 at 22-pin connector. See Fig 1. Connect voltmeter leads to terminals No. 3 and 12.
- Measure voltage while pressing and releasing hazard switch. Battery voltage should be present only when hazard switch is depressed. If voltage is not as specified, A/C ECU is faulty.