Schematic Reference: Exterior Lights Schematics

Did you perform the Lighting System Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

Press down the brake pedal.

Do all of the stop lamps illuminate?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

Is only one lamp inoperative?

Go to Step 4

Go to Step 5

1. Disconnect the inoperative stoplamp.
2. Probe the stop lamp supply voltage circuit of the inoperative stoplamp with test lamp that is connected to a good ground.
3. Press down the brake pedal.

Does the test lamp illuminate?

Go to Step 9

Go to Step 10

1. Disconnect the brake switch.
2. Probe the battery positive voltage circuit of the brake switch with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 6

Go to Step 7

Connect a 15 amp fused jumper wire between the battery positive voltage circuit of the brake switch and the stop lamp supply voltage circuit.

Do the stop lamps illuminate?

Go to Step 8

Go to Step 11

Test the stop lamp supply voltage circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 14

Go to Step 12

Inspect for poor connections at the harness connector of the brake switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 14

Go to Step 13

Repair an open or high resistance in the ground circuit of the inoperative stop lamp. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 14

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Repair an open or high resistance in the stop lamp supply voltage circuit of the inoperative stoplamp. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 14

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Repair an open or high resistance in the stop lamp supply voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 14

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Repair an open, high resistance, or short to ground in the battery positive voltage circuit of the brake switch. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 14

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Replace the brake switch. Refer to Stop Lamp Switch Replacement in Hydraulic Brakes.

Did you complete the replacement?

Go to Step 14

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Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3