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 relay operates.
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Tests for voltage at the coil side of the relay.
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Verifies that the control module is providing ground to the relay.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Exterior Lights Schematics Connector End View Reference: Master Electrical Component List in Wiring Systems | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
2 |
Do the stop lamps operate properly? | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 3 |
Press and release the brake pedal. Does the bass relay turn ON and OFF? | Go to Step 6 | Go to Step 4 | |
Does the test lamp illuminate? | Go to Step 5 | Go to Step 14 | |
Does the test lamp turn ON and OFF? | Go to Step 12 | Go to Step 9 | |
6 | Probe the switch side supply voltage circuit of the bass relay with a test lamp that is connected to a good ground. Does the test lamp illuminate? | Go to Step 7 | Go to Step 15 |
7 | Connect a 10-amp fused jumper between the switch side supply voltage circuit of the bass relay and the stop lamp switch signal circuit of the bass relay. Do the stop lamps illuminate? | Go to Step 12 | Go to Step 8 |
8 |
Does the test lamp illuminate? | Go to Step 11 | Go to Step 10 |
9 | Test the control circuit of the bass relay for an open or a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 20 | Go to Step 13 |
10 | Test the stop lamp switch signal circuit for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 20 | Go to Step 16 |
11 | Inspect for poor connections at the stop lamp. 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 |
12 | Inspect for poor connections at the bass 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 20 | Go to Step 17 |
13 | Inspect for poor connections at the harness connector of the electronic brake control module (EBCM). 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 19 |
14 | Repair the open circuit in the coil side supply voltage circuit of the bass relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 20 | -- |
15 | Repair the open circuit in the switch side supply voltage circuit of the bass relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 20 | -- |
16 | Repair the open circuit in the ground circuit of the inoperable stop lamp. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 20 | -- |
17 | Replace the bass relay. Refer to Relay Replacement in Wiring Systems. Did you complete the replacement? | Go to Step 20 | -- |
18 | Replace the inoperable stop lamp. Refer to Tail Lamp Replacement and High Mount Stop Lamp Replacement .
Did you complete the replacement? | Go to Step 20 | -- |
19 |
Did you complete the replacement? | Go to Step 20 | -- |
20 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 2 |
