1. PWM Identification & Characteristics
Definition: Pulse-width modulation (PWM) is a power delivery method used in 2019 or newer GM Trucks(e.g., Silverado，GMC，RAM, Ford) to control LED lighting circuits.
Key Symptom:
- Multimeter may show 12V+ at the backup light circuit, but the actual power is pulsed (not continuous).
- Car LEDs illuminate, but cameras fail to power on or exhibit intermittent operation.
2. Verification Method
Consult your vehicle manufacturer/dealer to confirm if your RV/tow vehicle uses PWM for lights.
Diagnostic Test:
If a camera works when directly connected to a 12V battery but fails when wired to the vehicle, PWM interference is likely.
3. Recommended Solutions
A. 7-Way Adapter (Plug-and-Play Fix)
Function: Converts PWM power to stable 12V output.
Installation: Connects between the vehicle’s 7-pin trailer plug and camera wiring.
Best for: Temporary or non-invasive setups.
B. Hardwired PWM Filter (Permanent Solution)
Product Example: 12V PWM Filter (search "PWM Filter" on etrailer).
Installation Steps:
- Locate the backup light power wire behind the camera.
- Splice the filter in-line between the vehicle’s power source and camera.
- Secure connections with heat-shrink tubing or waterproof crimps.
- Advantage: Provides clean, steady 12V power regardless of vehicle PWM.
4. Troubleshooting Notes
If using a filter/adapter and issues persist:
- Verify ground connection (resistance <0.5Ω to chassis).
- Check for voltage drop (>11V required at camera under load).
For further assistance, provide:
✓ Vehicle make/model/year
✓ Camera system details
✓ Multimeter readings (key ON, circuit active).