Code
B1436
ALFA ROMEO
B — Body
Wiper speed relay coil
Views:
UK: 2
EN: 6
RU: 2
AI status
Completed
Completed
100%
Causes
- Defective wiper speed relay (coil open or shorted)
- Corroded/loose connector or poor pin contact at the relay socket
- Damaged wiring (open, short to ground or battery, high resistance) between relay and control module or ground
- Blown fuse or poor power supply to relay
- Faulty wiper control module or driver transistor
- Excessive current draw from a seized or mechanically overloaded wiper motor
Symptoms
- Wipers fail to operate at one or more speeds
- Wipers stuck on a single speed (often high or low)
- Intermittent wiper operation or wipers stop working entirely
- Audible clicking from relay socket or no click when wipers commanded
- Related dashboard warning or stored body control module faults
What to check
- Retrieve and record fault codes with a diagnostic scanner; note freeze-frame if present
- Visually inspect relay, relay socket and wiring harness for corrosion, damage, loose pins or water ingress
- Check relevant fuses for continuity and proper seating
- Operate wipers while listening for relay click at the relay location
- Swap with a known good identical relay (if available) and re-check operation and codes
- Measure battery voltage at relay supply terminal with ignition/wipers ON
Signal parameters
- Coil resistance (typical relay): ~20–200 Ω (varies by relay design) — compare to service spec
- Supply voltage to relay common pin: ~12–14.5 V (battery voltage with ignition ON)
- Control/coil activation voltage: should see near 12 V or a switched ground on coil control when relay is commanded (varies by module design)
- Activation behavior: steady energize while wiper speed selected (may be PWM in some systems)
- If coil shows open or very high resistance, coil is likely failed; very low resistance indicates internal short
Diagnostic algorithm
- Read and record codes; clear and attempt to re-create the fault. Note when and how the fault occurs.
- Visual inspection: check relay, socket, wiring, fuses, and grounds for damage or corrosion. Repair obvious problems and retest.
- With ignition ON, probe relay socket: confirm battery supply at the common pin and check the control pin while operating the wipers. If supply is present but control never changes, suspect control module/wiring.
- Remove relay and measure coil resistance on the relay itself. If out of range, replace relay and retest.
- If relay coil checks OK, install relay and measure voltage at coil terminals in-situ while wipers commanded. If voltage never appears, perform continuity test back to module and check ground path.
- Swap with a known-good identical relay or jumper the coil control (only if safe and you know the wiring) to determine if relay cures the issue. Do not bypass safety circuits permanently.
- If wiring and relay are good but the coil control is not being driven, check communications and outputs from the wiper control module; inspect for additional module codes (U-codes).
- Check wiper motor current draw. If motor draws excessive current, repair or replace motor as required and replace any relays damaged by overload.
- After repairs, clear codes and verify full range of wiper speeds and operation over multiple cycles and environmental conditions.
Likely causes
- Relay coil open or internally shorted
- Corroded or loose relay socket/connector pins
- Broken or shorted control wire between module and relay coil
- Blown supply fuse or poor battery/ignition feed to relay
Fault status
Status
Wiper speed relay coil circuit fault — possible open/short or poor connection in relay/supply/control circuit. Inspect relay, socket, wiring, fuses and control module.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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