What Does B1502 Mean?
This code indicates that the Body Control Module (BCM) has detected an abnormal short circuit to ground in the left turn signal lamp circuit. The BCM monitors the electrical current flow through the turn signal circuit and sets this code when it detects current flowing directly to ground instead of through the lamp bulb, indicating a wiring fault or component failure. This prevents proper operation of the left turn signal system.
Common Causes
45%
Damaged or pinched wiring harness causing bare wire contact with vehicle chassis or metal components
30%
Failed turn signal bulb socket with internal short or corrosion creating ground path
15%
Corroded or damaged connector terminals at bulb socket or BCM creating intermittent ground fault
10%
Failed Body Control Module with internal circuit fault
Diagnostic Steps
1
Step 1: Perform visual inspection of left turn signal lamp assembly, socket, and visible wiring for obvious damage, melted components, or pinched wires against metal surfaces
2
Step 2: Disconnect the left turn signal bulb socket connector and use a digital multimeter to measure resistance from the turn signal wire (output from BCM) to chassis ground with ignition off - reading should be infinite (open circuit); any measurable resistance indicates a short to ground in the harness
3
Step 3: If Step 2 shows infinite resistance, inspect the bulb socket itself for corrosion, damaged terminals, or signs of water intrusion; test socket resistance to ground separately - should also be infinite
4
Step 4: Check BCM connector terminals for corrosion, pushed-back pins, or moisture; wiggle test harness while monitoring resistance to identify intermittent short locations
5
Step 5: If external wiring tests good, disconnect BCM connector and measure resistance from BCM turn signal output pin to ground - should be infinite; low resistance indicates internal BCM failure
6
Step 6: Repair identified short circuit (wire repair, socket replacement, or BCM replacement), clear codes, and verify left turn signal operation through multiple cycles to confirm repair
Estimated Repair Cost
$75 - $450
Parts + labor, varies by vehicle and location
This code indicates that the Body Control Module (BCM) has detected an abnormal short circuit to ground in the left turn signal lamp circuit. The BCM monitors the electrical current flow through the turn signal circuit and sets this code when it detects current flowing directly to ground instead of ...
The most common cause of B1502 (Lamp Turn Signal Left Circuit Short To Ground) is: Damaged or pinched wiring harness causing bare wire contact with vehicle chassis or metal components
Typical repair costs for B1502 range from $75 to $450, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Not safe to drive without functioning turn signals as this creates a significant traffic safety hazard and is illegal in all jurisdictions. Other drivers cannot anticipate your lane changes or turns, greatly increasing collision risk. Repair immediately before operating the vehicle.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1502 to identify the root cause.
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Quick Info
Category
Body
System
Exterior Lighting System
Difficulty
Type
Manufacturer
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