What Does B1215 Mean?
This code indicates that the Body Control Module (BCM) has detected a short to battery voltage in the running board lamp circuit. This means that the circuit is receiving constant battery power when it should not be, typically due to damaged wiring insulation or a faulty component allowing current to flow directly from the battery positive to the lamp circuit. The BCM monitors the circuit for abnormal voltage conditions and sets this code when voltage is present when the lamps should be off or when voltage exceeds expected parameters.
Common Causes
45%
Damaged or chafed wiring harness causing wire insulation to contact battery positive voltage
30%
Failed running board lamp assembly with internal short to power
15%
Faulty BCM internal driver circuit or relay stuck closed providing constant power
10%
Corroded or damaged connector pins creating unintended power path
Diagnostic Steps
1
Step 1: Perform visual inspection of running board lamp assemblies, wiring harness, and connectors for obvious damage, corrosion, melted insulation, or signs of chafing against metal surfaces, particularly where harness routes along frame rails or vehicle underbody
2
Step 2: Disconnect the running board lamp connector(s) and use a digital multimeter to measure voltage at the lamp side connector with ignition off - should read 0V; if battery voltage (12-14V) is present, the short is between the BCM and the connector
3
Step 3: With lamp disconnected, check resistance between the lamp circuit wire and battery positive at the BCM connector - should read infinite resistance (OL); low resistance indicates short to power in the harness
4
Step 4: If harness tests good, reconnect and measure current draw on the lamp circuit with lamps commanded off - any current flow indicates faulty lamp assembly with internal short
5
Step 5: Isolate sections of wiring by disconnecting intermediate connectors and retesting to pinpoint exact location of short if harness is suspect
6
Step 6: After repair, clear codes, cycle the running board lamps on/off multiple times, and verify no voltage present when lamps are off and code does not return
Estimated Repair Cost
$100 - $450
Parts + labor, varies by vehicle and location
This code indicates that the Body Control Module (BCM) has detected a short to battery voltage in the running board lamp circuit. This means that the circuit is receiving constant battery power when it should not be, typically due to damaged wiring insulation or a faulty component allowing current t...
The most common cause of B1215 (Running Board Lamp Circuit Short to Battery) is: Damaged or chafed wiring harness causing wire insulation to contact battery positive voltage
Typical repair costs for B1215 range from $100 to $450, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to continue driving as this only affects courtesy lighting functionality. However, the short to battery could cause continuous drain on the battery, potentially leading to no-start conditions if left unrepaired, and poses minor fire risk if current draw is excessive.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1215 to identify the root cause.
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Quick Info
Category
Body
System
Body Electrical System - Exterior Lighting
Difficulty
Type
Manufacturer
Recommended Tools
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