B1245 — Wiper Rear Motor Run Relay Circuit Short to Battery

What does OBD2 code B1245 mean?

B1245 — Wiper Rear Motor Run Relay Circuit Short to Battery. A fault in the body electrical system. The car is usually drivable while you plan the repair. Typical causes: corroded or loose connectors, blown fuse or failed relay, body control module (BCM) fault.

Will B1245 clear itself?

Sometimes B1245 clears after a few drive cycles if the fault was intermittent — for example a loose connector or a tank of bad fuel. The underlying cause usually remains, so the code tends to return. Clear it once; if it comes back, diagnose rather than erase it repeatedly.

How do I diagnose B1245 myself?

Start with a scan: confirm B1245, save the freeze frame and note any companion codes. Then inspect the wiring and connectors related to the body electrical system, and verify the suspect component against live data before buying parts.

Is it safe to drive with B1245?

Usually safe to drive — body codes rarely affect drivability. Exceptions: exterior lighting and wipers in bad weather, and central locking faults that can leave the car unsecured.

What is the most common cause of B1245?

The most common causes are: corroded or loose connectors, blown fuse or failed relay, body control module (BCM) fault.

When your OBD2 scanner pulls code B1245, it means the vehicle's body control module has detected a problem with the rear wiper motor's run relay circuit. Specifically, the system has identified an abnormal voltage condition—a short to battery—which indicates that power is reaching the relay circuit when it should not be. This is classified as a body electrical fault, separate from powertrain or emissions-related codes.

The body control module continuously monitors the rear wiper circuit, watching for expected behavior during each drive cycle. If the module sees voltage readings that fall outside the manufacturer's calibrated parameters for too long, it logs B1245 and may illuminate the dashboard warning light. The freeze frame data stored alongside the code is particularly valuable—it captures the exact operating conditions at the moment the fault occurred, including engine speed, load, temperature, and vehicle speed. That snapshot gives you a starting point for reproducing the failure.

Symptoms of B1245

• The rear wiper fails to operate or works only intermittently
• The wiper motor may run continuously without responding to switch commands
• Other body electrical functions connected to the same circuit can be affected
• The check engine or body warning light remains illuminated
• No effect on engine performance or drivability in most cases
• The rear wiper may stop mid-stroke or fail to return to the park position

Common Causes

The most frequent culprit behind B1245 is damaged or corroded wiring in areas exposed to moisture and movement. Door jambs, tailgate hinges, and the channels around the rear hatch are particularly vulnerable because flexing and water intrusion degrade insulation over time. Loose or oxidized connectors at the rear wiper motor or relay also trigger this code regularly. A blown fuse or failed relay removes proper circuit control, forcing voltage to take alternate paths and creating the short condition the module detects. While less common, the body control module itself can develop internal faults that produce false B1245 readings. Wiring chafing from contact with sharp metal edges or aftermarket accessories is another frequent source of shorts in this circuit.

How to Diagnose B1245

1. Connect your OBD2 scanner and verify that B1245 is the only code present, then record all freeze frame data before clearing anything. This preserved snapshot tells you whether the fault happened at idle, highway speed, or during a specific weather condition.
2. Search for technical service bulletins specific to your vehicle make, model, and model year. Many manufacturers have published updates or known fixes for recurring B1245 complaints, which can save hours of diagnostic time.
3. Perform a thorough visual inspection of the wiring harness serving the rear wiper motor and its run relay. Look for cracked insulation, green corrosion buildup, and any signs that wires have been rubbing against metal brackets or body panels.
4. Wiggle-test the connectors at both ends of the circuit while monitoring live data on your scanner. Watch for the wiper operation PID to change suddenly, which confirms an intermittent connection.
5. Check the fuse and relay associated with the rear wiper circuit. Swap the relay with an identical unit from another system to see if the code disappears, confirming a failed relay.
6. Clear B1245 after your inspection, then operate the vehicle through a complete drive cycle that matches the conditions in your freeze frame data. If the code returns, the fault is confirmed and active.

Repair Options and Costs

Repair costs for B1245 vary significantly depending on which component is actually at fault. Here are typical scenarios at independent shop labor rates:

• Wiring repair or connector replacement: $80–$250. Most affordable when the issue is exposed, damaged wires or a single corroded connector. Labor involves tracing the harness, splicing, sealing, and reconnecting.
• Rear wiper switch or actuator replacement: $120–$450. If the switch itself is sending incorrect signals or the motor run relay is mechanically failed, this is the targeted fix.
• Body control module repair or replacement: $300–$900. BCM faults are less common but require programming or calibration after installation, which adds to labor time.

Total Cost Summary

For most vehicles, expect to pay between $80 and $900 to resolve B1245. The majority of cases fall in the $120–$250 range where wiring or connector issues are the root cause. Spending time on careful diagnosis before purchasing parts prevents the expensive scenario of replacing a perfectly good body control module.

Can You Drive with B1245?

B1245 carries a short severity rating. The rear wiper circuit does not affect engine operation, transmission function, or braking systems, so your vehicle remains mechanically driveable. However, consider the practical implications: a non-functional rear wiper in rain or snow significantly reduces rear visibility. Central locking faults sometimes logged under related body codes can leave the vehicle unsecured. Use your best judgment based on weather conditions and have the code investigated before your next long trip.

Related OBD2 Codes

• B1200: Climate Control Pushbutton Circuit Failure
• B1201: Fuel Sender Circuit Failure
• B1202: Fuel Sender Circuit Open
• B1203: Fuel Sender Circuit Short To Battery
• B1204: Fuel Sender Circuit Short To Ground
• B1205: EIC Switch-1 Assembly Circuit Failure