B1721

Code

LAND ROVER B — Body

seat switch, rear seat

Brand: LAND ROVER

Type: B — Body

Views: UK: 15 EN: 40 RU: 16

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Page language: EN

Causes

Open or short in the rear seat switch wiring or connector
Contaminated, corroded, or loose connector at the switch or control module
Failed rear seat switch (mechanical or internal electrical fault)
Blown fuse or loss of power/ground to the switch circuit
Faulty seat control module or related body control module
Intermittent connection due to water ingress or wiring chafe

Symptoms

Rear seat feature (folding, reclining, heating or adjustment) does not operate from the rear switch
Intermittent operation of rear seat functions
Warning message or symbol related to rear seat on the instrument panel
Related features operate from other controls but not from the rear switch
DTC B1721 stored in diagnostic memory

What to check

Read and record freeze frame and all stored codes with a manufacturer-level scan tool
Verify whether the fault is permanent or intermittent (clear code and re-test)
Visually inspect rear seat switch, surrounding trim, and wiring for damage, contamination or water ingress
Inspect connectors at the switch and at the seat/body control module for corrosion, bent pins or poor engagement
Check fuses and power supply circuits for the seat switches
Perform basic continuity/resistance checks on wiring from switch to module and to ground/power

Signal parameters

Supply voltage to switch: approximately battery voltage (nominal 11–14 V) when ignition on
Switch output: expected to toggle between supply voltage and ground or between defined logic levels (model dependent)
Resistance across closed switch: near 0 Ω (or low ohms); open switch: high/OL
Wake/communication: CAN or LIN messages present on network if the switch is networked (check with scope/scan tool)
Typical diagnostic trouble criteria: stuck/high/low/open circuit or implausible signal compared to expected range

Diagnostic algorithm

Connect a manufacturer-level scan tool. Read and record DTCs, freeze frame data and live data for the rear seat switch input.
Recreate symptom while watching live data. Attempt operation of the rear seat switch and observe if the switch state changes in the data stream.
Perform a visual inspection: remove trim to access the switch and wiring. Look for chafing, pin damage, water, or corrosion.
With ignition off, disconnect switch connector and inspect pins. Clean/repair as needed. Reconnect and check for secure fit.
Check power and ground at the switch connector with a multimeter (ignition on). Verify expected supply voltage and good ground.
Measure continuity/resistance between switch output pin and the module input pin. Wiggle harness through its range while watching continuity to identify intermittent faults.
If switch is accessible, bench-test the switch with a multimeter to confirm it changes state (resistance or voltage) when actuated.
If wiring and switch test OK, verify communications to the controlling module (CAN/LIN) and check for related module faults.
If module input is not receiving a valid signal but wiring and switch are good, consider module reprogramming or replacement per manufacturer guidance.
After repairs, clear codes, operate the system through several cycles and confirm the DTC does not return.

Likely causes

Corroded or disconnected connector at the rear seat switch
Failed rear seat switch (most common on vehicles with heavy use)
Damaged wiring harness where it flexes (seat base/harness area)
Failed module input or internal module fault

Fault status

⚠️ Status

Stored — Rear seat switch circuit fault detected (open/short/invalid signal). May be intermittent or permanent depending on wiring/connector or component condition.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5 - 2.0 hours

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Browse 413 LAND ROVER manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

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B1721 — seat switch, rear seat