Code
B1743
MITSUBISHI
B — Body
Hazard lamp fuse blowing out
Views:
UK: 3
EN: 12
RU: 6
AI status
Completed
Completed
100%
Causes
- Short to ground in the hazard/turn‑signal wiring (chafed or pinched harness)
- Faulty hazard switch or flasher/hazard relay with internal short
- One or more bulbs with internal short or incorrect (over‑wattage) bulbs installed
- Corroded or water‑ingress damaged lamp sockets or connectors creating a short
- Aftermarket accessories tied into the circuit incorrectly
- Damaged fuse holder or poor contact causing arcing and repeated fuse failure
Symptoms
- Fuse for hazard/indicator circuit blows immediately or shortly after hazards are switched on
- No hazard or turn signal operation when fuse is blown
- Fuse blows only when specific lamp(s) or trailer connector are connected
- Visible arcing, melted fuse holder, burning smell near fuse box or lamp
- Intermittent operation of indicators/hazard before fuse failure
What to check
- Confirm correct fuse rating (do not replace with higher amperage fuse to 'fix' problem)
- Visually inspect fuse and fuse holder for signs of melting, burning or poor contact
- Inspect all lamp bulbs and sockets (front/rear/side) for corrosion, broken filaments or conductive debris
- Disconnect hazard relay/ flasher module and check whether fuse still blows
- Disconnect lamp connectors and trailer connector, then operate hazards to isolate the faulted section
- Perform a wiring inspection along common chafe points (doors, fenders, rear quarter, trunk) looking for damaged insulation
Signal parameters
- Typical bulb current: 21 W incandescent ≈ 1.7 A per lamp at 12 V (check vehicle-specific bulb wattage)
- Hazard circuit total current (all bulbs active) commonly up to ~6–10 A for standard incandescent setups
- Common fuse rating for hazard/turn circuits: typically 10 A–15 A (vehicle-specific — consult manual)
- Fuse voltage at supply with ignition on and hazards activated: ~12 V (no more than ~0.5 V drop across good fuse/holder)
- Ground resistance for lamp circuit: ideally
Diagnostic algorithm
- Do not replace fuse with a higher amperage. Replace blown fuse with correct rating to proceed.
- With ignition off, visually inspect fuse, fuse holder, and adjacent wiring for heat damage. Disconnect battery negative before major repairs.
- Remove all external loads: unplug front/rear lamp connectors and any trailer or accessory connections tied to the circuit.
- Replace fuse and activate hazards. If fuse does NOT blow, reconnect loads one at a time (or one lamp at a time) to identify which lamp/connector causes the fault.
- If fuse still blows with all lamps disconnected, pull the hazard/flasher relay and retest. If fuse no longer blows suspect relay/module or upstream short near fuse box.
- If a specific lamp causes the blow, inspect that lamp socket and wiring for corrosion, water, or pinched wires; repair or replace socket and harness as required.
- If fault is not isolated to a single lamp, systematically follow the harness from fuse box toward lamps, using an ohmmeter to check for unintended continuity to ground with the circuit disconnected (fused circuit = remove fuse first).
- Use an inline ammeter to confirm current draw when circuit is active; if high current persists with lamps disconnected, suspect short in harness or BCM and consider disconnecting BCM outputs for further isolation.
- Repair damaged wiring (replace sections or use proper splice/resealing techniques), replace faulty relay or sockets, and reassemble. Clear any BCM codes and retest.
- After repair, perform a final road/test check of hazard and turn signals and inspect fuse holder for heat or signs of recurring trouble.
Likely causes
- Wiring chafe near door hinge, front fender, or rear lamp harness where movement fatigues insulation
- Lamp socket corroded by moisture leading to short when vehicle vibrates or when wet
- Stuck relay contacts in the hazard flasher causing constant high current draw
- Incorrect bulb replacement (higher wattage halogen) or LED retrofit without proper resistors
- Aftermarket trailer connector or accessory incorrectly wired to the hazard circuit
- Short inside BCM or connector pin short at fuse/relay box (less common)
Fault status
Status
Hazard lamp circuit overcurrent — fuse blows when hazard switch activated (possible short, faulty lamp/relay, or wiring fault).
Repair difficulty: Medium
Diagnostic time: 1-3 hours
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Code
B1743
Other
B — Body
Mirror Passenger Vertical Switch Circuit Short To Battery
Views:
UK: 21
EN: 36
RU: 22
AI status
Completed
Completed
100%
Causes
- Short to ground in the hazard/turn‑signal wiring (chafed or pinched harness)
- Faulty hazard switch or flasher/hazard relay with internal short
- One or more bulbs with internal short or incorrect (over‑wattage) bulbs installed
- Corroded or water‑ingress damaged lamp sockets or connectors creating a short
- Aftermarket accessories tied into the circuit incorrectly
- Damaged fuse holder or poor contact causing arcing and repeated fuse failure
Symptoms
- Fuse for hazard/indicator circuit blows immediately or shortly after hazards are switched on
- No hazard or turn signal operation when fuse is blown
- Fuse blows only when specific lamp(s) or trailer connector are connected
- Visible arcing, melted fuse holder, burning smell near fuse box or lamp
- Intermittent operation of indicators/hazard before fuse failure
What to check
- Confirm correct fuse rating (do not replace with higher amperage fuse to 'fix' problem)
- Visually inspect fuse and fuse holder for signs of melting, burning or poor contact
- Inspect all lamp bulbs and sockets (front/rear/side) for corrosion, broken filaments or conductive debris
- Disconnect hazard relay/ flasher module and check whether fuse still blows
- Disconnect lamp connectors and trailer connector, then operate hazards to isolate the faulted section
- Perform a wiring inspection along common chafe points (doors, fenders, rear quarter, trunk) looking for damaged insulation
Signal parameters
- Typical bulb current: 21 W incandescent ≈ 1.7 A per lamp at 12 V (check vehicle-specific bulb wattage)
- Hazard circuit total current (all bulbs active) commonly up to ~6–10 A for standard incandescent setups
- Common fuse rating for hazard/turn circuits: typically 10 A–15 A (vehicle-specific — consult manual)
- Fuse voltage at supply with ignition on and hazards activated: ~12 V (no more than ~0.5 V drop across good fuse/holder)
- Ground resistance for lamp circuit: ideally
Diagnostic algorithm
- Do not replace fuse with a higher amperage. Replace blown fuse with correct rating to proceed.
- With ignition off, visually inspect fuse, fuse holder, and adjacent wiring for heat damage. Disconnect battery negative before major repairs.
- Remove all external loads: unplug front/rear lamp connectors and any trailer or accessory connections tied to the circuit.
- Replace fuse and activate hazards. If fuse does NOT blow, reconnect loads one at a time (or one lamp at a time) to identify which lamp/connector causes the fault.
- If fuse still blows with all lamps disconnected, pull the hazard/flasher relay and retest. If fuse no longer blows suspect relay/module or upstream short near fuse box.
- If a specific lamp causes the blow, inspect that lamp socket and wiring for corrosion, water, or pinched wires; repair or replace socket and harness as required.
- If fault is not isolated to a single lamp, systematically follow the harness from fuse box toward lamps, using an ohmmeter to check for unintended continuity to ground with the circuit disconnected (fused circuit = remove fuse first).
- Use an inline ammeter to confirm current draw when circuit is active; if high current persists with lamps disconnected, suspect short in harness or BCM and consider disconnecting BCM outputs for further isolation.
- Repair damaged wiring (replace sections or use proper splice/resealing techniques), replace faulty relay or sockets, and reassemble. Clear any BCM codes and retest.
- After repair, perform a final road/test check of hazard and turn signals and inspect fuse holder for heat or signs of recurring trouble.
Likely causes
- Wiring chafe near door hinge, front fender, or rear lamp harness where movement fatigues insulation
- Lamp socket corroded by moisture leading to short when vehicle vibrates or when wet
- Stuck relay contacts in the hazard flasher causing constant high current draw
- Incorrect bulb replacement (higher wattage halogen) or LED retrofit without proper resistors
- Aftermarket trailer connector or accessory incorrectly wired to the hazard circuit
- Short inside BCM or connector pin short at fuse/relay box (less common)
Fault status
Status
Hazard lamp circuit overcurrent — fuse blows when hazard switch activated (possible short, faulty lamp/relay, or wiring fault).
Repair difficulty: Medium
Diagnostic time: 1-3 hours
Similar codes
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
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