Headlight Dimmer Switch Circuit: Procedure
- READ VALUE USING TECHSTREAM (HEADLIGHT DIMMER SWITCH)
- Using the Techstream, read the Data List. Refer to DATA LIST / ACTIVE TEST
.MAIN BODY
Tester Display Measurement Item/Range Normal Condition Diagnostic Note Dimmer SW Headlight dimmer switch high signal / ON or OFF ON: Headlight dimmer switch in high or high flash
OFF: Headlight dimmer switch in low- Passing Light SW Headlight dimmer switch high flash signal / ON or OFF ON: Headlight dimmer switch in high flash
OFF: Headlight dimmer switch not in high flash- Front Fog Light SW Front fog light switch signal / ON or OFF ON: Front fog light switch on
OFF: Front fog light switch off- Auto Light SW* Headlight dimmer switch AUTO signal / ON or OFF ON: Headlight dimmer switch in AUTO
OFF: Headlight dimmer switch not in AUTO- Head Light SW (Head) Headlight dimmer switch head signal / ON or OFF ON: Headlight dimmer switch in head
OFF: Headlight dimmer switch not in head- Head Light SW (Tail) Headlight dimmer switch tail signal / ON or OFF ON: Headlight dimmer switch in tail or head
OFF: Headlight dimmer switch not in tail or head- - *: w/ Automatic Light Control System
OK
The display is as specified in the normal condition column.
NG → See step 2
OK → See step 4
- Using the Techstream, read the Data List. Refer to DATA LIST / ACTIVE TEST
.
- INSPECT HEADLIGHT DIMMER SWITCH ASSEMBLY
- Remove the headlight dimmer switch. Refer to REMOVAL .
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Switch Condition Specified Condition 4 (BFG) - 3 (LFG) Fog light switch on Below 1 Ω 11 (HU) - 12 (EL) Headlight dimmer switch high Below 1 Ω Headlight dimmer switch high flash 17 (HF) - 12 (EL) Headlight dimmer switch high flash Below 1 Ω 18 (T) - 12 (EL) Headlight dimmer switch tail Below 1 Ω Headlight dimmer switch head 19 (A) - 12 (EL)* Headlight dimmer switch AUTO Below 1 Ω 20 (H) - 12 (EL) Headlight dimmer switch head Below 1 Ω 4 (BFG) - 3 (LFG) Fog light switch off 10 kΩ or higher 18 (T) - 12 (EL) Headlight dimmer switch off 10 kΩ or higher 19 (A) - 12 (EL)* 20 (H) - 12 (EL) - *: w/ Automatic Light Control System
TEXT IN ILLUSTRATION*A w/ Automatic Light Control System
NG → See step 5
OK: Go to next step
- CHECK HARNESS AND CONNECTOR (HEADLIGHT DIMMER SWITCH ASSEMBLY - MAIN BODY ECU AND BODY GROUND)
- Disconnect the F22 headlight dimmer switch connector.
- Disconnect the F9 main body ECU connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition F22-4 (BFG) - F9-27 (FFOG) Always Below 1 Ω F22-11 (HU) - F9-5 (HU) Always Below 1 Ω F22-17 (HF) - F9-8 (HF) Always Below 1 Ω F22-18 (T) - F9-30 (TAIL) Always Below 1 Ω F22-19 (A) - F9-28 (A)* Always Below 1 Ω F22-20 (H) - F9-29 (HEAD) Always Below 1 Ω F22-4 (BFG) - Body ground Always 10 kΩ or higher F22-11 (HU) - Body ground Always 10 kΩ or higher F22-17 (HF) - Body ground Always 10 kΩ or higher F22-18 (T) - Body ground Always 10 kΩ or higher F22-19 (A) - Body ground* Always 10 kΩ or higher F22-20 (H) - Body ground Always 10 kΩ or higher F22-12 (EL) - Body ground Always Below 1 Ω F22-3 (LFG) - Body ground Always Below 1 Ω - *: w/ Automatic Light Control System
NG → REPAIR OR REPLACE HARNESS OR CONNECTOR
OK → See step 6
- PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to PROBLEM SYMPTOMS TABLE
- REPLACE HEADLIGHT DIMMER SWITCH ASSEMBLY. Refer to REMOVAL
- REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU). Refer to REMOVAL