Schematic Reference: Exterior Lights Schematics

Did you review the Exterior Lighting System Description and Operation and perform the necessary inspections?

Go to Step 2

Go to Symptoms - Lighting Systems

1. Place the ignition switch in the RUN position.
2. Observe the stop lamps.
3. Press and release the brake pedal.

Do the stoplamps operate properly?

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

Go to Step 3

Determine if only one of the stop lamp is inoperative or all stop lamp are inoperative.

Is only one stop lamp inoperative?

Go to Step 6

Go to Step 4

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

Does the test lamp illuminate?

Go to Step 5

Go to Step 10

Install a fused jumper between the battery positive voltage circuit and the stop lamp switch signal circuit of the stoplamp switch connector. Refer to Circuit Testing in Wiring Systems.

Do the stop lamp illuminate?

Go to Step 11

Go to Step 13

Are the tail lamps inoperative?

Go to Step 7

Go to Step 8

1. Remove the inoperative tail lamp bulb.
2. Using a test lamp, probe the stoplamp switch signal circuit and ground circuit of the inoperative tail lamp bulb socket.

Does the test lamp illuminate?

Go to Step 19

Go to Step 8

1. Disconnect the inoperative tail lamp assembly connector or center high mounted stop lamp connector (CHMSL).
2. Probe the stop lamp switch signal circuit of the tail lamp or CHMSL connector with a test lamp that is connected to ground.

Does the test lamp illuminate?

Go to Step 9

Go to Step 16

Using a test lamp, probe between the stop lamp switch signal circuit and the ground circuit of the tail lamp or CHMSL connector.

Does the test lamp illuminate?

Go to Step 12

Go to Step 15

Test for an open or high resistance in the battery positive voltage circuit of the stop lamp switch. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 20

Go to Step 14

Inspect for poor connections at the harness connector of the stop lamp 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 20

Go to Step 18

Inspect for poor connections at the harness connector of the tail lamp assembly or CHMSL. 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 20

Go to Step 17

Repair a open or high resistance in the stop lamp switch signal circuit of the stop lamp switch. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Is the repair complete?

Go to Step 20

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Repair a short to ground in one of the following circuits:

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Is the repair complete?

Go to Step 20

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

Is the repair complete?

Go to Step 20

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Repair a open or high resistance in the stoplamp switch signal circuit of the inoperative stop lamp. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Is the repair complete?

Go to Step 20

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Replace the inoperative tail lamp or CHMSL. Refer to Tail Lamp Replacement or High Mount Stop Lamp Replacement .

Did you complete the repair?

Go to Step 20

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Adjust or replace the stoplamp switch. Refer to Stop Lamp Switch Replacement in Hydraulic Brakes.

Is the repair complete?

Go to Step 20

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Replace the inoperative stoplamp bulb.

Did you complete the repair?

Go to Step 20

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Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2