AUDIO AND VISUAL SYSTEM > Illumination Circuit |

| 1.CHECK ILLUMINATION |
Check if the illumination for the radio receiver assembly, steering pad switch LH or other parts (heater control switch, defogger switch, etc.) come on when the light control switch is turned to the HEAD or TAIL position.
| Result | Proceed to |
| Illumination comes on for all components except steering pad switch. | A |
| Illumination comes on for all components except radio receiver. | B |
| Illumination comes on for all components except steering pad switch and radio receiver. | |
| No illumination (radio receiver, heater control switch, defogger switch, etc.) comes on. | C |
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| A | |
| 2.CHECK HARNESS AND CONNECTOR (SPIRAL CABLE - RADIO RECEIVER - BATTERY AND BODY GROUND) |
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Disconnect the D19 spiral cable sub-assembly connector.
Disconnect the D63 radio receiver assembly connector.
Measure the resistance according to the value(s) in the table below.
| Tester Connection | Condition | Specified Condition |
| D19-4 (EAU) - D63-6 (SWG) | Always | Below 1 Ω |
| D19-4 (EAU) - Body ground | Always | 10 kΩ or higher |
Measure the voltage according to the value(s) in the table below.
| Tester Connection | Switch Condition | Specified Condition |
| D19-12 (IL+2) - Body ground | Light control switch OFF | Below 1 V |
| Light control switch TAIL or HEAD | 11 to 14 V |
| *1 | Front view of wire harness connector (to Radio Receiver Assembly) |
| *2 | Front view of wire harness connector (to Spiral Cable Sub-Assembly) |
Reconnect the spiral cable sub-assembly connector.
Reconnect the radio receiver assembly connector.
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| OK | |
| 3.INSPECT STEERING PAD SWITCH LH |

| *1 | Steering Pad Switch LH |
Disconnect the V1 steering pad switch LH connector.
Connect the positive (+) lead to terminal 5 (IL+2) and the negative (-) lead to terminal 8 (EAU) of the steering pad switch LH connector.
Check if the illumination for the steering pad switch LH comes on.
Reconnect the steering pad switch LH connector.
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| OK | |
| 4.INSPECT SPIRAL CABLE SUB-ASSEMBLY |
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Disconnect the V1 and D19 spiral cable sub-assembly connectors.
Measure the resistance according to the value(s) in the table below.
| Tester Connection | Condition | Specified Condition |
| V1-5 (IL+2) - D19-12 (IL+2) | Spiral cable is turned 2.5 rotations counterclockwise | Below 1 Ω |
| Spiral cable is centered | ||
| Spiral cable is turned 2.5 rotations clockwise | ||
| V1-8 (EAU) - D19-4 (EAU) | Spiral cable is turned 2.5 rotations counterclockwise | |
| Spiral cable is centered | ||
| Spiral cable is turned 2.5 rotations clockwise |
| *1 | Component without harness connected (Spiral Cable Sub-Assembly) |
| *2 | Steering Pad Switch Side |
| *3 | Vehicle Side |
Reconnect the spiral cable sub-assembly connectors.
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| OK | ||
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| 5.CHECK HARNESS AND CONNECTOR (RADIO RECEIVER - BATTERY AND BODY GROUND) |
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Disconnect the D61 radio receiver assembly connector.
Measure the voltage according to the value(s) in the table below.
| Tester Connection | Switch Condition | Specified Condition |
| D61-10 (ILL+) - Body ground | Light control switch TAIL or HEAD | 11 to 14 V |
| Light control switch OFF | Below 1 V |
Measure the resistance according to the value(s) in the table below.
| Tester Connection | Switch Condition | Specified Condition |
| D61-7 (GND) - Body ground | Always | Below 1 Ω |
| *1 | Front view of wire harness connector (to Radio Receiver Assembly) |
Reconnect the radio receiver assembly connector.
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| OK | ||
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