B1215: Running Board Lamp Circuit Short to Battery
The B1215 code indicates that the control module has detected a short circuit to battery positive (B+) in the running board lamp circuit. This means there is unwanted electrical continuity between the lamp circuit and a constant voltage source, causing the module to read a higher voltage than expected during the circuit diagnostic check. A short to battery in this circuit prevents the running board lamps from turning off properly, as voltage remains present regardless of the controller's command signal. The DTC is stored when output circuit monitoring confirms the line stays high (B+) when it should be low or pulse-width modulated.
1. Commonly Affected Makes
2. Most Common Causes
- Short circuit in the wiring harness between the running board lamp circuit and a B+ source
- Lighting control relay or module with welded or stuck-closed internal contacts
- Internal short circuit in the running board lamp assembly or its connector
- Damaged connector terminal or pin contacting adjacent battery voltage wires
3. Symptoms You Will Notice
- Running board lamps stay on continuously
- Running board lamps fail to turn on or off as commanded
4. Step-by-Step Diagnosis
Verify the B1215 code and check for related DTCs
Inspect the running board lamp wiring harness for damage or shorts to B+
Test the lighting control relay/module for stuck contacts
Check the lamp assembly and connector for internal shorts or corrosion
5. Frequently Asked Questions
Is it safe to drive?▼
Yes, it is generally safe to drive with this code, as it only affects the running board lamps. However, the lamps may remain on, which could drain the battery if left unattended.
How much does it cost to fix?▼
Repair costs typically range from $100 to $300, depending on the cause and labor rates. Simple wiring repairs may be on the lower end, while replacing a control module or lamp assembly could be higher.