B1821
Low Severity (Level 2)Wiper Rear Motor Up Relay Coil Circuit Short To Ground
B1821 usually means wiper Rear Motor Up Relay Coil Circuit Short To Ground.
Can you still drive with B1821?
⚠️Short-distance driving is usually OK, but have this diagnosed within a week to prevent further damage.
Typical repair cost: $60 – $500
Severity Level 2 — Low
This code indicates a minor issue that is unlikely to cause immediate driveability problems. You can typically continue driving but should have the vehicle inspected at your earliest convenience.
Common Symptoms
- Windshield wipers blowing fuses when activated
- Wipers won't park (return to rest position) when turned off
- Windshield wipers not working, stuck mid-cycle, or only working on one speed
- Zero voltage on the wiper/washer system circuit — short pulls signal to ground
Possible Causes
- Chafed or pinched wire in the wiper/washer system circuit — wire insulation worn through, copper touching vehicle chassis/ground
- Failed wiper motor with internal short to ground — most common when the component gets wet or overheats
- Corrosion in the electrical connector allowing current to leak to the connector shell/ground
- Damaged wiring harness where it passes through a body panel grommet or near a sharp metal edge
Common Fixes
- Scan vehicle with a professional-grade OBD2 scanner to read all stored codes and freeze frame data — note the conditions when the code set ($12-103 at shop, free at auto parts store for basic scan)
- Visually inspect the wiper/washer system wiring harness and connectors — look for chafed wires, melted insulation, green corrosion, loose pins, or rodent damage (often free to check yourself, $83 diagnostic fee at shop)
- Repair or replace damaged section of wiring harness where short is located — solder and heat-shrink all connections, don't use crimp connectors on critical circuits ($139-428 depending on accessibility)
- If wiper motor is internally shorted, replace with a quality OEM or OEM-equivalent aftermarket unit ($50-400)
- Clean all ground points related to the wiper/washer system — remove bolt, sand contact surface to bare metal, apply dielectric grease, and torque to spec ($40-118 at shop)
Estimated Repair Cost
These are estimated costs based on generic repair data. Actual costs may vary depending on your vehicle, location, and labor rates.
Frequently Asked Questions
What does B1821 mean?
B1821 stands for "Wiper Rear Motor Up Relay Coil Circuit Short To Ground". B1821 usually means wiper Rear Motor Up Relay Coil Circuit Short To Ground.
Can you drive with B1821?
Short-distance driving is usually OK, but have this diagnosed within a week to prevent further damage.
How much does it cost to fix B1821?
Repair costs for B1821 typically range from $60 to $500, depending on your vehicle make, model, and local labor rates. Common fixes include: Scan vehicle with a professional-grade OBD2 scanner to read all stored codes and freeze frame data — note the conditions when the code set ($12-103 at shop, free at auto parts store for basic scan); Visually inspect the wiper/washer system wiring harness and connectors — look for chafed wires, melted insulation, green corrosion, loose pins, or rodent damage (often free to check yourself, $83 diagnostic fee at shop); Repair or replace damaged section of wiring harness where short is located — solder and heat-shrink all connections, don't use crimp connectors on critical circuits ($139-428 depending on accessibility).
Will B1821 clear itself?
Explore Repair Costs
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