Test Procedure
WARNING: This page is about a different car, the 2003 Lexus ES 300 and 2002 Lexus ES 300. However, it is still accessible from the selected car via links, so may be relevant.
- If the positive (+) lead and the negative (-) lead are incorrectly connoted, the indicator light lamp does not light up.
- Voltage of 5 volts or more will damage the indicator lamp. If the voltage is too low, the lamp will not light up.
- Apply about 5 volts positive voltage between positive (+) lead to terminal LP (A14-10) and negative (-) lead to terminal GND (A15-21) of the security indicator light. See Fig 1. If the security indicator light comes on, go to the next step. If the security indicator light does not come on, replace the heater control housing sub-assembly. See AUTOMATIC A/C-HEATER SYSTEMS article in HVAC.
- Disconnect the anti-theft warning ECU assembly connector. Disconnect heater control housing sub-assembly A14 connector. Check the continuity between terminal IND (T6-12) of anti-theft warning ECU assembly connector and terminal LP (A14-10) of heater control housing sub-assembly A14 connector. See Fig 2. If continuity exists, go to the next step. If continuity does not exist, repair or replace the harness and connector as necessary.
- Disconnect heater control housing sub-assembly A15 connector. See Fig 3. Check continuity between terminal GND (A15-21) of heater control housing sub-assembly A15 and body ground. If continuity exists, check and replace the anti-theft warning ECU assembly. If continuity does not exist, repair or replace the harness and connector as necessary.
NOTE:
Fig 1: Identifying Anti-Theft Warning ECU Assembly Terminal LP & Heater Control Housing Sub-Assembly Connector Terminal IND (Component Side Shown)