Toyota 4Runner: Headlight Dimmer Switch Circuit
DESCRIPTION
The main body ECU receives the following signals:
- Headlight dimmer switch tail, head, AUTO*, high or high flash signal
- Front fog light switch signal
- *: w/ Automatic Light Control System
WIRING DIAGRAM
PROCEDURE
|
1. |
READ VALUE USING TECHSTREAM (HEADLIGHT DIMMER SWITCH) |
(a) Using the Techstream, read the Data List (See page
.gif)
).
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.
| OK | .gif) |
PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE |
|
.gif)
|
2. |
INSPECT HEADLIGHT DIMMER SWITCH ASSEMBLY |
|
(a) Remove the headlight dimmer switch (See page
|
|
(b) 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
|
*A |
w/ Automatic Light Control System |
| NG | |
REPLACE HEADLIGHT DIMMER SWITCH ASSEMBLY |
|
|
3. |
CHECK HARNESS AND CONNECTOR (HEADLIGHT DIMMER SWITCH ASSEMBLY - MAIN BODY ECU AND BODY GROUND) |
(a) Disconnect the F22 headlight dimmer switch connector.
(b) Disconnect the F9 main body ECU connector.
(c) 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
| OK | |
REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) |
| NG | |
REPAIR OR REPLACE HARNESS OR CONNECTOR |
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