Test Description
The numbers below refer to the step numbers on the diagnostic table.
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Listen for an audible click when the center high mounted stop lamp (CHMSL) relay operates. Repeat as necessary.
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Tests for voltage at the control side of the CHMSL relay.
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Verifies the ground to the CHMSL relay.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Exterior Lights Schematics Connector End View Reference: Master Electrical Component List in Wiring Systems | |||
1 | Did you review the exterior lighting description and operation and perform the necessary inspections? | Go to Step 2 | |
2 |
Do the stop lamps operate properly? | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 3 |
3 | Do the turn signals operate properly? | Go to Step 4 | |
Press down the brake pedal and release. Does the center high mounted stop lamp (CHMSL) relay turn ON and OFF with the brake pedals position? | Go to Step 7 | Go to Step 5 | |
Does the test lamp illuminate? | Go to Step 6 | Go to Step 10 | |
Does the test lamp turn ON and OFF with the brake pedals position? | Go to Step 12 | Go to Step 17 | |
7 | Probe the CHMSL relay switch side battery positive voltage circuit with a test lamp that is connected to a good ground. Does the test lamp illuminate? | Go to Step 8 | Go to Step 15 |
8 | Connect a 15-amp fused jumper between the CHMSL relay switch side battery positive voltage circuit and the stop sw brake priority circuit. Do both of the stop lamps illuminate? | Go to Step 12 | Go to Step 9 |
9 |
Does the test lamp illuminate? | Go to Step 14 | Go to Step 16 |
10 | Test the stop lamp switch supply voltage circuit for a high resistance, an open or a short to ground. Did you find and correct the condition? | Go to Step 21 | Go to Step 11 |
11 | Test the battery positive voltage circuit of the stop lamp switch for a high resistance, an open or a short to ground. Did you find and correct the condition? | Go to Step 21 | Go to Step 13 |
12 | Inspect for poor connections at the CHMSL relay. 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 21 | Go to Step 18 |
13 | 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 21 | Go to Step 19 |
14 | Inspect for poor connections at the harness connector of the turn signal/multifunction 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 21 | Go to Step 20 |
15 | Repair the open circuit in the CHMSL relay switch side battery positive voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 21 | -- |
16 | Repair the open circuit in the stop sw brake priority circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 21 | -- |
17 | Repair the open or a short to voltage in the CHMSL relay control side ground circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 21 | -- |
18 | Replace the CHMSL relay. Refer to Relay Replacement in Wiring Systems. Did you complete the replacement? | Go to Step 21 | -- |
19 | Replace the stop lamp switch. Refer to Stop Lamp Switch Replacement . Did you complete the replacement? | Go to Step 21 | -- |
20 | Replace the turn signal/multifunction switch. Refer to Turn Signal Multifunction Switch Replacement in Steering Wheel and Column. Did you complete the replacement? | Go to Step 21 | -- |
21 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 2 |
