B1214

Code

Other B — Body

Running Board Lamp Circuit Failure

Brand: Other

Type: B — Body

Views: UK: 18 EN: 47 RU: 43

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Page language: EN

Causes

Blown fuse or tripped circuit protection
Failed lamp (bulb or LED module)
Open or shorted wiring harness to running board lamp
Corroded, loose, or damaged connector/ground
Water intrusion in lamp housing or connector
Faulty body control module (BCM) or lamp driver output

Symptoms

Running board/step lamp does not illuminate
Lamp works intermittently or only with pressure on connector
Related lamp or convenience lighting faults present
Possible stored or intermittent B1214 trouble code
Fuses appear blown repeatedly after replacement

What to check

Retrieve stored and pending codes with an OBD/diagnostic scanner and note freeze-frame or test results
Visually inspect lamp assembly, connector, wiring harness, and running board area for damage or water intrusion
Check fuse(s) and any inline fusible links related to running board lighting
Inspect and wiggle connectors while observing lamp operation for intermittent behavior
Measure voltage at lamp connector with lamp switch/door ajar condition to simulate normal operation
Measure continuity and resistance between lamp and chassis ground and between lamp and BCM output

Signal parameters

Lamp supply voltage (connector pin): ~11–14 V with lamp relay/supply ON (12 V nominal)
Ground continuity: near 0 ohms from lamp negative to chassis ground
Control signal from BCM/lamp driver: either battery-switched supply or switched ground; may be PWM for LED modules (frequency varies by vehicle manufacturer)
Typical current draw: incandescent bulb tens to hundreds of milliamps; LED modules often 50–500 mA depending on design
Open-circuit: infinite resistance between supply and lamp or between lamp and ground

Diagnostic algorithm

Confirm symptom and note conditions when fault occurred (doors open/closed, vehicle on/off)
Use a scan tool to read and record B1214 and any related codes; clear codes and attempt to re-create fault
Visually inspect lamp, lens, housing, and connector for corrosion, water, or physical damage; repair as needed
Check fuses and any associated relays; replace any blown fuses and retest; if fuse blows again, proceed carefully for short diagnosis
With lamp connector disconnected, measure supply voltage at the harness with the circuit commanded ON. If no voltage, trace back to fuse/relay/BCM
Connect a known-good lamp or apply bench 12V to the lamp connector to verify lamp module function. If known-good lamp lights, suspect wiring/driver/BCM
Check ground at lamp: measure resistance from lamp ground pin to chassis ground (
Perform continuity/resistance checks between BCM/lamp driver output and lamp connector; repair any opens or high-resistance segments
If harness wiring and lamp module test good, check BCM output with oscilloscope or multimeter for expected voltage/PWM signal; compare to manufacturer specs if available
Repair or replace damaged wiring, connector, or lamp module. If BCM/lamp driver is suspected after all wiring and lamp checks, refer to manufacturer procedures for module testing and replacement
Clear codes, cycle lighting function several times, and road-test or exercise door/lamp functions to verify repair

Likely causes

Failed lamp module (LED) or filament bulb
Corroded/loose connector at the running board lamp
Open or short in wiring due to abrasion or impact
Blown inline fuse or fusible link

Fault status

⚠️ Status

Stored when the body/lighting control detects an abnormal condition in the running board lamp circuit (open, short, high resistance, or driver failure). Code may be set as current or intermittent depending on fault persistence.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-2.0 hours