Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Diagnostic Aids
2005 Saturn Relay AWDSECTION Diagnostic Aids
- An open or short to ground in the battery positive voltage circuit of the STOP/TURN fuse will cause all 4 turn signal DTCs.
- Check the LF turn lamp bulb. If the bulb is open, DTC B3948 will be set.
- If the DTC is a history DTC, the fault may be intermittent. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
- An intermittent short to ground or an open in the following locations may cause an intermittent malfunction to occur:
- The BCM
- The underhood electrical center
- The left front turn signal lamp supply voltage circuit
DTC B3948
| 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 |
|
Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 3 |
| 3 |
|
Go to Step 4 | Go to Step 8 |
| 4 | Test the ground circuit of the inoperative lamp for 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 10 | Go to Step 5 |
| 5 | Test the left front turn signal supply voltage circuit for the following:
Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? |
Go to Step 10 | Go to Step 7 |
| 6 | Test the battery positive voltage circuit from the STOP/TURN fuse for a short to ground or an open. Did you find and correct the condition? |
Go to Step 10 | Go to Step 7 |
| 7 | Inspect for a high resistance or an open at the harness connector of the body control module (BCM). 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 10 | Go to Step 9 |
| 8 | Replace the bulb. Refer to Daytime Running Lamp, Park and Turn Signal Lamp and Bulb Replacement - Front . Did you complete the replacement? |
Go to Step 10 | - |
| 9 | Replace the BCM. Refer to Control Module References
in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? |
Go to Step 10 | - |
| 10 |
|
Go to Step 3 | System OK |
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.