B109D

Code

LAND ROVER B — Body

Rear courtesy light

Brand: LAND ROVER

Type: B — Body

Views: UK: 22 EN: 27 RU: 23

AI status

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Page language: EN

Causes

Burnt-out or failed rear courtesy bulb or LED module
Open or shorted wiring in the rear courtesy light circuit
Corroded or loose connector/terminal at the lamp or harness
Poor or open ground at the lamp or chassis
Blown fuse or faulty relay protecting the courtesy circuit
Faulty body control module (BCM) or BCM output driver

Symptoms

Rear courtesy light does not illuminate
Intermittent operation or flickering of rear courtesy light
Related interior lights behave abnormally
DTC B109D stored in BCM/body module memory
Possible increased battery drain if circuit is shorted

What to check

Read and record freeze-frame/self-test data from BCM (if available)
Inspect the rear courtesy lamp(s) visually for damage or corrosion
Check fuse(s) for the interior/courtesy lighting circuit
Verify connector engagement and condition at the lamp and harness
Check for water or debris inside the lamp housing
Perform a wiggle test on wiring harness while monitoring lamp and fault status

Signal parameters

Expected supply voltage at lamp connector: ~11–14.5 V with circuit energized
Ground continuity: near 0 ohms between lamp ground pin and chassis ground
Incandescent bulb cold resistance: typically low (fractions to a few ohms); operating current often 0.5–2 A
LED module: low current draw, typically
BCM output: switches to ground or 12 V depending on design — verify per vehicle wiring diagram

Diagnostic algorithm

Retrieve and record fault code and associated data with a capable scanner; note whether the fault is current or historic.
Visually inspect the rear courtesy lamp(s), lens, and housing for damage, moisture, or corrosion.
Check the appropriate fuse(s) for continuity; replace if blown and retest.
Remove the lamp assembly and inspect the bulb or LED module; replace with a known good bulb/module and see if code clears.
With ignition on (or circuit energized), measure voltage at the lamp power pin and verify good chassis ground at the ground pin.
If no supply voltage, back-probe harness to trace power feed toward fuse/relay and BCM; repair any open or shorted wiring.
If supply and ground present but lamp does not light, check bulb socket and pin continuity; replace socket or repair pins as needed.
If lamp and wiring check good, inspect BCM output using scope or multimeter while commanding light on via scanner; compare to expected waveform/voltage.
Check for aftermarket accessories or recent body repairs that could have disturbed wiring or grounds.
After repairs, clear the DTC with a scanner and perform function tests and a road/usage cycle if required to confirm the fault does not return.

Likely causes

Failed lamp/LED module (most common)
Connector corrosion or pin pushed out at rear lamp
Open ground or poor chassis ground near the lamp
Broken wire due to door hinge or luggage area movement
BCM output fault or incorrect module programming (less common)

Fault status

⚠️ Status

Rear courtesy light circuit fault detected — inspect lamp, connectors, wiring, fuses and BCM output. Replace or repair defective parts and clear code.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5 - 1.5 hours

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Repair manuals

Manual library for LAND ROVER

320

Browse 320 LAND ROVER manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

LAND ROVER

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