Headlight Beam Level Control Ecu Circuit
WARNING: This page is about a different car, the 2003 Lexus RX 300 and 2002 Lexus RX 300. However, it is still accessible from the selected car via links, so may be relevant.
- Disconnect the connector from the ECU and inspect the connector on the wiring harness side. See CONNECTOR IDENTIFICATION . See INSPECTING HEADLIGHT BEAM LEVEL CONTROL ECU CIRCUIT (CONNECTOR DISCONNECTED) table. If the circuit is not as specified, go to the next step.INSPECTING HEADLIGHT BEAM LEVEL CONTROL ECU CIRCUIT (CONNECTOR DISCONNECTED)
Tester Connection Condition Specified Condition 9 (RHG) - 12 (RH4) Ignition Switch OFF 26-30 Ohms 22 (LHG) - 25 (LH4) Ignition Switch OFF 26-30 Ohms 9 (RHG) - 13 (RH2) Ignition Switch OFF 26-30 Ohms 22 (LHG) - 23 (LH3) Ignition Switch OFF 26-30 Ohms 22 (LHG) - 26 (LH2) Ignition Switch OFF 26-30 Ohms 9 (RHG) - 11 (RH1) Ignition Switch OFF 26-30 Ohms 22 (LHG) - 24 (LH1) Ignition Switch OFF 26-30 Ohms 9 (RHG) - 10 (RH3) Ignition Switch OFF 26-30 Ohms 7 (HDLP) - 1 (GND) Ignition Switch ON & Light Control Switch HEAD Less Than 1.5 Volts 18 (SHR) - 16 (SGF) Ignition Switch OFF 3.5-6.5 k Ohms 20 (SBR) - 16 (SGF) Ignition Switch OFF 3.5-6.5 k Ohms 1 (GND) - Body Ground Constant Continuity - Connect the connector to the ECU and inspect the connector. See INSPECTING HEADLIGHT BEAM LEVEL CONTROL ECU CIRCUIT (CONNECTOR CONNECTED) table. If the circuit is not as specified, replace the ECU.INSPECTING HEADLIGHT BEAM LEVEL CONTROL ECU CIRCUIT (CONNECTOR CONNECTED)
Tester Connection Condition Specified Condition 14 (IG) - 1 (GND) Ignition Switch ON B+ Voltage 12 (RH4) - 9 (RHG) Ignition Switch ON, When Keep & Bounce The Vehicle *1 Pulse Generation (1) 25 (LH4) - 22 (LHG) Ignition Switch ON, When Keep & Bounce The Vehicle *1 Pulse Generation (1) 13 (RH2) - 9 (RHG) Ignition Switch ON, When Keep & Bounce The Vehicle *1 Pulse Generation (1) 23 (LH3) - 22 (LHG) Ignition Switch ON, When Keep & Bounce The Vehicle *1 Pulse Generation (1) 18 (SHR) - 16 (SGF) Ignition Switch ON Approximately 2.5 Volts 20 (SBR) - 16 (SGF) Ignition Switch ON 5 Volts 16 (SGF) - 1 (GND) Ignition Switch OFF Continuity 7 (HDLP) - 1 (GND) Ignition Switch ON & Light Control Switch HEAD Below 1.5 V 26 (LH2) - 22 (LHG) Ignition Switch ON, When Keep & Bounce The Vehicle *1 Pulse Generation (1) 11 (RH1) - 9 (RHG) Ignition Switch ON, When Keep & Bounce The Vehicle *1 Pulse Generation (1) 24 (LH1) - 22 (LHG) Ignition Switch ON, When Keep & Bounce The Vehicle *1 Pulse Generation (1) 10 (RH3) - 9 (RHG) Ignition Switch ON, When Keep & Bounce The Vehicle *1 Pulse Generation (1) 18 (WNG) - 20 (E1) Ignition Switch ON No Continuity 6 (SPDR) - 1 (GND), 5 (SPDL) - 1 (GND) Vehicle Driving At About 18 mph (30 km) *2 Pulse Generation (1) 1 (GND) - Body Ground Ignition Switch OFF Continuity (1) See Fig 1.