What Does B1575 Mean?
B1575 indicates the Body Control Module (BCM) has detected an abnormal signal or open/short circuit in the parking lamp input circuit. This code is triggered when the BCM cannot properly read the status of the parking lamp switch or receives voltage/resistance values outside the expected range. The parking lamp system includes the switch, wiring harness, and associated control circuits that activate the vehicle's parking/position lights.
Common Causes
35%
Faulty or corroded parking lamp switch contacts causing intermittent or no signal to BCM
30%
Damaged wiring harness, chafed insulation, or broken wires between parking lamp switch and BCM
20%
Corroded or loose electrical connectors at parking lamp switch or BCM causing high resistance
15%
Failed Body Control Module unable to properly process parking lamp input signals
Diagnostic Steps
1
Step 1: Perform visual inspection of parking lamp switch, wiring harness, and all connectors from switch to BCM for obvious damage, corrosion, or loose connections. Check for chafed wires near moving components or sharp edges.
2
Step 2: Using a digital multimeter, backprobe the parking lamp switch connector and verify proper voltage supply (typically 12V) on the input wire with ignition on. Verify proper continuity to ground on the ground circuit (should read less than 1 ohm).
3
Step 3: Test the parking lamp switch operation by measuring resistance across switch terminals while cycling the switch through all positions. Compare readings to manufacturer specifications (typically open circuit when off, closed/near zero ohms when on).
4
Step 4: Check for voltage at the BCM input terminal for the parking lamp circuit with switch activated. Should read battery voltage when switch is on, near zero volts when off. If voltage is correct at BCM but code persists, suspect BCM internal fault.
5
Step 5: Perform continuity test of the complete circuit from switch to BCM with switch disconnected and BCM connector removed. Should read less than 5 ohms end-to-end. Check for shorts to ground or power (should read open circuit/infinite resistance).
6
Step 6: After repairs, clear codes, cycle parking lamps on/off multiple times, and verify proper operation. Road test vehicle and monitor for code recurrence using scan tool live data.
Estimated Repair Cost
$75 - $450
Parts + labor, varies by vehicle and location
B1575 indicates the Body Control Module (BCM) has detected an abnormal signal or open/short circuit in the parking lamp input circuit. This code is triggered when the BCM cannot properly read the status of the parking lamp switch or receives voltage/resistance values outside the expected range. The ...
The most common cause of B1575 (Lamp Park Input Circuit Failure) is: Faulty or corroded parking lamp switch contacts causing intermittent or no signal to BCM
Typical repair costs for B1575 range from $75 to $450, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle is safe to drive, but parking lamps may not function properly which reduces visibility to other drivers during dusk/dawn conditions or when parked. Repair should be completed promptly to maintain proper vehicle lighting for safety and legal compliance.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1575 to identify the root cause.
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Quick Info
Category
Body
System
Exterior Lighting System
Difficulty
Type
Manufacturer
Recommended Tools
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