Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Headlights/Daytime Running Lights (DRL) Schematics | |||
1 | Did you review the daytime running lights (DRL) operation and perform the necessary inspections? | Go to Step 2 | |
2 |
Do the DRL's illuminate? | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 3 |
3 | Is the park brake indicator illuminated? | Go to Park Brake Indicator Always On in Park Brakes | Go to Step 4 |
4 |
Does the test lamp illuminate? | Go to Step 23 | Go to Step 5 |
5 |
Does the test lamp illuminate? | Go to Step 6 | Go to Step 14 |
6 | Connect a fused jumper wire between the switch side input circuit and the switch side output circuit of the DRL ON relay. Do the DRL's illuminate? | Go to Step 20 | Go to Step 7 |
7 |
Does the test lamp illuminate? | Go to Step 8 | Go to Step 24 |
8 | Connect a fused jumper wire between the switch side input circuit and the switch side output circuit of the DRL OFF relay. Do the DRL's illuminate? | Go to Step 9 | Go to Step 25 |
9 | Probe the coil side voltage supply circuit of the DRL OFF relay with a test lamp that is connected to a good ground. Does the test lamp illuminate? | Go to Step 10 | Go to Step 26 |
10 | Connect a test lamp between the coil side voltage supply circuit and the coil side control circuit of the DRL OFF relay. Does the test lamp illuminate? | Go to Step 21 | Go to Step 11 |
11 | Does the vehicle being worked on have air brakes? | Go to Step 27 | Go to Step 12 |
12 |
Does the test lamp illuminate? | Go to Step 13 | Go to Step 28 |
13 |
Does the test lamp illuminate? | Go to Step 29 | Go to Step 18 |
14 |
Does the test lamp illuminate? | Go to Step 15 | Go to Step 16 |
15 |
Does the test lamp illuminate? | Go to Step 22 | Go to Step 30 |
16 |
Does the test lamp illuminate? | Go to Step 17 | Go to Step 31 |
17 |
Does the test lamp illuminate? | Go to Step 19 | Go to Step 32 |
18 | Test for a short to ground in the coil side control circuit of the DRL OFF 2 relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 38 | Go to Step 33 |
19 | Test for a short to ground in the coil side control circuit of the lighting relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 38 | Go to Step 34 |
20 | Inspect for poor connections at the DRL ON 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 38 | Go to Step 35 |
21 | Inspect for poor connections at the DRL OFF 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 38 | Go to Step 36 |
22 | Inspect for poor connections at the DRL series dropping resistor. 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 38 | Go to Step 37 |
23 | Repair a short to ground in the coil side control circuit of the DRL ON relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 38 | -- |
24 | Repair an open or high resistance in the switch side input circuit of the DRL OFF relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 38 | -- |
25 | Repair an open or high resistance in the switch side output circuit of the DRL OFF relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 38 | -- |
26 | Repair an open, high resistance, or short to ground in the coil side voltage supply circuit of the DRL OFF relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 38 | -- |
27 | Repair an open or high resistance in the coil side control circuit of the DRL OFF relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 38 | -- |
28 | Repair an open or high resistance in the switch side input circuit of the DRL OFF 2 relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 38 | -- |
29 | Repair an open or high resistance in the switch side output circuit of the DRL OFF 2 relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 38 | -- |
30 | Repair an open or high resistance in the switch side input circuit of the DRL ON relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 38 | -- |
31 | Repair an open or high resistance in the switch side input circuit of the lighting relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 38 | -- |
32 | Repair an open or high resistance in the voltage input circuit of the DRL series dropping resistor. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 38 | -- |
33 | Replace the DRL OFF 2 relay. Did you complete the replacement? | Go to Step 38 | -- |
34 | Replace the lighting relay. Did you complete the replacement? | Go to Step 38 | -- |
35 | Replace the DRL ON relay. Did you complete the replacement? | Go to Step 38 | -- |
36 | Replace the DRL OFF relay. Did you complete the replacement? | Go to Step 38 | -- |
37 | Replace the DRL series dropping resistor. Refer to Daytime Running Lamps (DRL) Resistor Replacement . Did you complete the replacement? | Go to Step 38 | -- |
38 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 3 |
