Main Switch

Measure switch resistance.

Driver's switch: 

Fig 1: Main Switch: Driver's Switch Inspection Chart

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Front passenger's switch: 

Fig 2: Main Switch: Front Passenger's Switch Inspection Chart

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Rear left switch: 

Fig 3: Main Switch: Rear Left Switch Inspection Chart

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Rear right switch: 

Fig 4: Main Switch: Rear Right Switch Inspection Chart

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If NG, replace the main switch.