What Are GM Battery Current Sensors?
These are non-intrusive Hall effect sensors designed to sit around the main battery cable and report current to the car’s ECU. Their data is crucial for modern “smart charging” systems that dynamically adjust alternator output to reduce load, improve fuel efficiency, and maintain optimal battery condition. Both 13505369 and 10306471 are commonly found in models from Chevrolet, GMC, Buick, Cadillac, Pontiac, Saturn, and Hummer.
Pinout Reference
- VCC – +5V Power Input
- GND – Ground
- SIGNAL – Digital PWM Output
Digital Protocol
The sensor outputs a PWM signal on the SIGNAL pin:
- Frequency: ~120–128 Hz (can vary slightly by unit)
- Duty Cycle: 50% at 0A (no current), proportional up/down for charge/discharge
- Signal type: 5V logic PWM
The duty cycle directly reflects in/out battery current; a positive (charging) or negative (discharging) current shifts the duty cycle up or down from 50%. Example waveform capture below:
Typical readings:
- 50% Duty Cycle ≈ 0A (idle/stable battery)
- Range: ±60A
