B1503

Code

Other B — Body

Lamp Turn Signal Right Circuit Failure

Brand: Other

Type: B — Body

Views: UK: 29 EN: 71 RU: 42

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Page language: EN

Right turn indicator lamp (rear/front) does not illuminate
Fast or irregular turn signal flash rate
Turn signal indicator on instrument cluster may not illuminate or may flash erratically
Turn/hazard lamps work intermittently or only when harness is manipulated
Associated warning/chime or stored DTC B1503

Scan for stored codes and pending faults; note freeze-frame data if available
Visually inspect right turn lamp (front and rear), socket, and connectors for corrosion, damage, or moisture
Check lamp bulb or LED module operation by bench-testing or swapping with known-good lamp
Check related fuses and relays for continuity and correct operation
Measure voltage at lamp socket with turn signal ON (battery present at feed pin?)
Check continuity from lamp connector to BCM output and from lamp ground to chassis ground

Supply voltage at lamp feed with turn signal ON: ~11–14 V (depending on battery/charging)
Incandescent lamp filament resistance (cold) typically a few ohms; operating current commonly ~0.5–3 A per lamp
LED lamp current: typically
Open-circuit: very high/infinite resistance between feed and bulb or no voltage at socket when ON
Short-to-ground: near 0 Ω between feed and chassis ground with fuse possibly blown or protection active

Read and record all BCM/lighting-related codes. Clear codes after recording and see if B1503 returns.
Confirm symptom: activate right turn signal and hazards; note which lamps (front/rear/cluster) fail or flash abnormally.
Visually inspect lamp assemblies, sockets, wiring, and connectors for corrosion, damage, or water intrusion. Repair as needed.
Remove lamp/bulb and bench-test the lamp on a known-good 12 V source or swap with the left-side lamp to verify lamp function.
With the turn signal ON, use a DVOM to measure voltage at the lamp feed terminal. If no voltage, trace back toward BCM checking continuity and fuses.
Check ground continuity from lamp ground terminal to chassis ground (
If feed voltage is present but lamp does not light and bulb tests good, check for short to ground on the feed (low resistance) or an open feed (infinite resistance) between lamp and BCM.
Inspect and test any inline connectors, splice points, and trailer harness connections. Repair damaged wiring or connectors.
Measure current draw of the lamp circuit to determine if load is within expected range (compare to incandescent vs LED expectations).
If wiring and lamp are verified good and correct, confirm BCM output using a scope or scan tool output test. Replace BCM only after verifying power, grounds, and wiring integrity.
After repairs, clear codes and retest operation and perform road test to ensure the code does not return.