B1720
Seat Driver Forward Switch Circuit Short To Ground
Body Chassis/Safety Seat Adjustment Circuit 🟢 Low — Fix at next service
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What This Actually Means
In plain language — no jargon

The driver's seat forward/backward adjustment switch has an electrical short to ground, meaning the circuit is bypassing its normal path and draining power to ground. It's like a water pipe that has a leak preventing water from reaching its destination.

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Symptoms You May Notice
3 known symptoms for this code
Seat lumbar/forward adjustment buttons unresponsive or inoperative
Seat control module warning light or B-series fault code displayed
Possible battery drain if short is continuous
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Embedded Systems Insight
What the ECU/ECM is actually computing

The body control module monitors the voltage signal from the driver seat forward switch circuit. It expects a normal high voltage signal when the switch is open and a specific lower voltage when activated. A short to ground keeps the signal at 0V continuously, triggering a fault.

Voltage & Parameter Thresholds

Parameter Normal Range Fault Condition
Switch Signal Voltage 12V open, 0-5V when activated normally Constant 0V or below 0.5V due to short path
Circuit Resistance High resistance when open, varies when switch engaged Near 0 ohms indicating direct ground short
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Diagnostic & DIY Fix Guide
Check these in order — from cheapest to most complex
1
Seat switch connector and wiring harness
Inspect and reseat the connector at the seat track motor or switch assembly to eliminate corrosion or loose contact.
2
Driver seat forward/backward switch assembly
Replace the faulty switch unit if contacts are shorted internally or wiring is damaged.
3
Wiring harness section between seat and body control module
Repair or replace damaged wiring insulation causing the ground short along the circuit path.