B1839

Code

Other B — Body

Wiper Rear Motor Circuit Failure

Brand: Other

Type: B — Body

Views: UK: 19 EN: 25 RU: 18

AI status

Completed

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Page language: EN

Causes

Blown fuse or faulty relay for rear wiper circuit
Open or shorted wiring between the BCM/switch and rear wiper motor
Corroded, loose, or water-damaged connector at the motor or module
Failed rear wiper motor (internal brushes, commutator, or gears)
Poor chassis ground at motor or module
Faulty wiper switch or body control module (BCM) output stage

Symptoms

Rear wiper does not operate at any switch position
Intermittent rear wiper operation or works only in one speed
Rear wiper stops mid-stroke or will not park correctly
Clicking relay sound or blown fuse when rear wiper selected
Excessive current draw or motor overheating
No response from rear wiper switch while front wipers work (if independent)

What to check

Visit vehicle with ignition on and wiper switch operated; note behavior
Inspect fuse box for blown fuse and replace with correct rating if blown
Check relay function (swap with identical relay or bench test)
Visually inspect wiring and connectors at rear wiper motor for corrosion, water ingress, damage, or melted insulation
Verify good chassis ground at motor and measure continuity to battery negative
Scan vehicle for related DTCs and read live data for rear wiper command and feedback (if available)

Signal parameters

Command voltage at motor supply: ~11–14 V with ignition ON and switch active
Ground continuity: near 0 ohms between motor ground terminal and battery negative
Motor resistance: low ohms between motor power and ground when stationary (manufacturer-specific)
Running current: typical running current of a small wiper motor (use clamp meter) — expect higher inrush at start, then lower steady current; abnormally high steady current indicates binding or motor fault
Park/position switch signal (if present): should change state when motor reaches park position (check with scan tool or multimeter)

Diagnostic algorithm

Retrieve all stored DTCs and freeze frame data; note any related body or communication codes.
Visually inspect rear wiper motor, connector, and wiring harness for corrosion, damage, or water entry; repair any damage and reseal connectors.
Check and replace fuse for rear wiper circuit if blown; verify fuse rating before replacing.
Verify relay operation: swap with known good identical relay or bench-test. Replace if intermittent or failed.
With connector disconnected, measure voltage at the wiper motor supply terminal while operating the switch; expected battery voltage (~11–14 V). If absent, trace back to relay/fuse/BCM.
Measure continuity/resistance of the feed and ground circuits from the motor connector to the controlling module/battery; repair open/shorts and poor contacts.
Backprobe motor connector and measure current draw with a clamp meter while operating; compare to expected behavior. High steady current indicates mechanical binding or internal motor fault.
Bench-test motor: apply fused 12 V and ground directly to motor to confirm reliable operation. Replace motor if it fails or draws excessive current.
If wiring, fuse, relay, and motor check good, inspect BCM output using a scope or consult wiring diagram to test driver transistor outputs; consider module programming or replacement as a last resort.
After repairs, clear codes, cycle ignition/wiper switch, and verify proper operation and that code does not return.

Likely causes

Failed rear wiper motor or internal motor short
Open/short in feed or ground conductors to rear wiper
Corroded/melted connector or pin causing intermittent contact
Blown fuse or stuck/failed wiper relay
Faulty BCM or control module driver circuit

Fault status

⚠️ Status

Body control module reports a failure in the rear wiper motor circuit — could be open, short, poor connection, or motor/driver fault. Further electrical diagnosis required.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.0 hours