B1758

Code

Other B — Body

Seat Driver Rear Down Circuit Open

Brand: Other

Type: B — Body

Views: UK: 20 EN: 31 RU: 27

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Page language: EN

Causes

Open or broken wiring in rear-down circuit
Corroded or disconnected connector at switch, motor or seat module
Failed seat switch (rear-down position)
Failed seat motor/actuator for rear down
Poor or missing ground
Blown fuse or fusible link

Symptoms

Rear portion of driver seat will not lower (rear down)
No audible motor noise when commanding rear-down
Related seat position warnings or message on dash (varies by vehicle)
Diagnostic trouble code B1758 stored, possibly with other seat circuit codes

What to check

Read and record all stored codes and freeze frame data with a scan tool
Visual inspection of seat wiring harness, connectors and switches for damage or corrosion
Check relevant fuses and fusible links
Operate the rear-down switch while observing for motor movement or noise
Backprobing: check for battery voltage at the switch and motor when the command is given
Perform continuity and resistance checks between switch, motor and control module ground

Signal parameters

Expected battery voltage at switch input: ~12 V (key on)
Motor supply when commanded: near battery voltage or PWM signal depending on vehicle
Circuit open: infinite resistance / OL on continuity test
Switch contact resistance when closed: low ohms (
Ground circuit resistance: low (

Diagnostic algorithm

Use a scan tool: confirm B1758 and note any related seat codes. Clear codes and re-run functional test to confirm repeat.
Visual inspection: examine harness along seat rails and under trim for damage, pinched wires, or disconnected connectors.
Check fuses: verify power feed fuse(s) for seat circuits and replace if blown.
Backprobe the rear-down switch connector: with switch commanded, verify switch sends voltage to motor/control module and returns to ground when not commanded.
Backprobe at seat motor/actuator: command rear-down while measuring voltage at motor connector. If no voltage present, trace back toward switch/module.
Continuity: with battery disconnected, measure continuity between switch, motor and module pins to find open circuit. Repair any broken wires or corroded pins.
Bench test motor: if wiring is good but motor does not run when directly powered (observing polarity), replace motor/actuator.
If wiring and motor are good, verify outputs from seat control or BCM. If module does not command the circuit correctly, consider module fault—verify ground and power to module before replacement.
After repairs, clear codes and perform multiple full-range seat function tests to confirm proper operation and no recurrence.

Likely causes

Broken or chafed wire in the harness between the switch and seat motor
Disconnected or corroded connector at the seat base
Failed rear-down travel motor or gear assembly
Failed seat position switch contacts

Fault status

⚠️ Status

Circuit open detected on driver seat rear-down circuit. Check wiring, connectors, fuses, switch and motor for open or high-resistance condition; replace or repair failed component(s) and re-test.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.0 hours