Passenger's Seatback Autoglide Forward Switch Circuit Short to Ground
The passenger seatback autoglide forward mechanism has an electrical short to ground, like a water leak in a pipe that's draining the circuit. The control module detects abnormally low resistance when it tries to signal the motor.
The ECM sends a control signal to the autoglide solenoid/motor and monitors the circuit resistance. A short to ground causes the signal voltage to drop prematurely and current draw to spike above normal limits. The module detects this abnormal condition and stores the fault.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Circuit Voltage | 12V when inactive, modulated PWM signal when active | Voltage drops to 0-2V or remains at ground potential |
| Circuit Resistance | Motor coil impedance 5-50 ohms | Resistance below 1 ohm indicating direct short path |
Code B1599 is a low-severity fault. Your vehicle is generally safe to drive to a workshop for diagnosis. However, do not ignore it indefinitely — low-severity codes often indicate developing problems that become expensive if neglected. Book a diagnostic appointment within 2–4 weeks. If you notice any additional symptoms (rough running, power loss, unusual smells), treat it as higher priority.
Once the fault is repaired, B1599 can be cleared using any OBD-II scanner. Connect the scanner, navigate to "Clear Codes" or "Erase DTCs," and confirm. The check engine light turns off immediately.
The code will return if the root cause was not actually fixed. The ECM re-detects the fault within 1–3 drive cycles and sets the code again.