Code
B1510
FIAT
B — Body
Hazard flasher switch circuit short to ground
Views:
UK: 6
EN: 9
RU: 3
AI status
Completed
Completed
100%
Causes
- Damaged or chafed wiring harness with conductor contacting chassis ground
- Faulty or water-damaged hazard flasher / hazard switch assembly
- Corroded or loose connector pins at switch or BCM
- Blown fuse or shorted flasher/relay
- Incorrect or damaged aftermarket electrical work (alarms, audio, wiring)
- Internal BCM/brake module input fault
Symptoms
- Hazard lights do not work or stop working when activated
- Turn signals or dash hazard indicator behave erratically
- Related fuses blow repeatedly
- Possible parasitic battery drain when vehicle off
- Associated BCM functions (e.g., alarm, central locking) may show faults or not operate
What to check
- Read stored DTCs with a compatible scan tool and note freeze-frame/occurrence count
- Visual inspection of hazard switch, connector, and wiring for damage, corrosion or water ingress
- Inspect related fuses and relays for correct rating and signs of damage
- Wiggle test wiring while observing lamp operation and scan tool live data
- Measure voltage at the switch connector with switch ON and OFF
- Check continuity between the circuit conductor and chassis ground (should be open when switch is disconnected)
Signal parameters
- Battery voltage present at supply terminal: ~12 V (vehicle on/off depending on design)
- Switch output when ON: near battery voltage at flasher input
- Switch output when OFF: open circuit (high resistance) to flasher input
- Continuity to chassis ground: near infinite (open) when switch disconnected; short to ground will show near 0 Ω
- Fuse rating: check vehicle-specific value (commonly 10 A or 15 A for body circuits)
Diagnostic algorithm
- Connect a diagnostic scanner, read/record all DTCs and clear codes after recording.
- Visually inspect hazard switch, surrounding trim, and wiring for damage, moisture, or corrosion. Remove switch to access connector.
- Check fuses/relays for the hazard/turn circuit. Replace any blown fuse only after confirming no persistent short.
- With ignition off, disconnect the hazard switch connector. Using an ohmmeter, measure resistance between the suspected circuit pin and chassis ground. A low resistance (~0 Ω) indicates a short to ground.
- If short present with switch disconnected, trace wiring toward BCM/relay: inspect harness along steering column, dash, and under-dash areas for chafing or pinched wires. Repair insulation or replace harness section as needed.
- If no short with switch disconnected, bench-test the switch for internal short by measuring continuity between terminals in OFF and ON positions. Replace switch if faulty.
- If wiring and switch appear good, backprobe the BCM/relay output with ignition on and hazard switch commanded. Verify proper voltage and check for intermittent shorts while wiggling harness. If BCM output is shorted internally, consider replacing or reprogramming module per manufacturer procedure.
- After repairs, clear codes, verify function of hazards and related systems, and perform a road or function test to confirm repair. Re-scan to ensure code does not return.
Likely causes
- Wiring harness rubbed through near steering column or dash causing conductor to ground
- Faulty hazard switch (internal short)
- Corroded connector at switch or BCM causing intermittent short
Fault status
Status
Hazard flasher switch circuit short to ground detected by body control module. Possible causes: wiring short to chassis, faulty switch, corroded connector, or BCM input fault. Operation of hazard lamps may be affected.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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