B1727
Seat Driver Rear Up Switch Circuit Short To Battery
Body Chassis/Safety Seat Control Circuit 🟢 Low — Fix at next service
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What This Actually Means
In plain language — no jargon

The seat's rear up switch is electrically shorted directly to battery power, like a wire touching the positive terminal when it shouldn't. The ECU can't control the seat properly because the circuit is stuck in an 'always on' state.

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Symptoms You May Notice
3 known symptoms for this code
Driver rear seat moves up unexpectedly or won't stop moving up
Seat control buttons unresponsive or behave erratically
Fault code stored in body control module
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Embedded Systems Insight
What the ECU/ECM is actually computing

The ECU monitors voltage on the rear seat up switch circuit, expecting it to toggle between ground and battery voltage based on button presses. A short to battery means the circuit stays at battery voltage constantly, preventing normal switching logic.

Voltage & Parameter Thresholds

Parameter Normal Range Fault Condition
Rear Up Switch Voltage 0V (off) to 12V (on) with button control Constant 12V+ with no variation
Switch Signal Resistance Open/high resistance when unpressed Continuous low resistance path to battery
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Diagnostic & DIY Fix Guide
Check these in order — from cheapest to most complex
1
Wiring harness connectors
Inspect and reseat the seat control module connectors for corrosion or loose pins.
2
Switch wiring and harness
Trace the rear up switch circuit for chafed insulation, melted wires, or pinched connections touching battery positive.
3
Rear seat up switch assembly
Replace the defective switch if wiring appears intact.