B1437 — Wiper Hi/Low Speed Relay Coil Circuit Short To Ground

B1437 — Wiper Hi/Low Speed Relay Coil Circuit Short To Ground. A fault in the ignition system. Short, gentle driving to a shop is usually possible. Typical causes: failed ignition coil or coil pack, faulty ignition control circuit in the ECM, worn spark plugs or wrong plug gap.

body electrical

Is it safe to drive?

Drive with caution Drive with caution and avoid load. Ignition faults cause misfires that quickly overheat and destroy the catalytic converter; if the Check Engine Light flashes, stop and fix it first.

How to diagnose with an OBD scanner

Read the code and freeze frame Connect an OBD2 scanner, confirm B1437 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
Check for companion codes and TSBs Related codes often reveal the real root cause. Also check manufacturer technical service bulletins (TSB) for your make and model — many B0xxx issues have factory fixes or software updates. Search by VIN on the manufacturer site or nhtsa.gov.
Inspect wiring and connectors Visually inspect the wiring harness and connectors related to the ignition system for damage, corrosion, chafing or poor contact.
Subsystem check Swap the coil to another cylinder and see if the fault code follows it.
Subsystem check Inspect spark plugs for wear, oil or carbon tracks and check plug gaps.
Verify the repair Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm B1437 does not return.

Approximate repair cost

Repair cost depends on which component actually failed. Typical scenarios for B1437 (parts and labor, USD, independent shop rates): Repair coil wiring or connector: $80–$250; Replace an ignition coil: $150–$380; Replace spark plugs: $90–$250. Overall, fixing B1437 usually costs between $80 and $380. An accurate diagnosis before buying parts saves money — the most expensive scenario is rarely the first one to check.

Common questions

What does OBD2 code B1437 mean?

How do I diagnose B1437 myself?

Start with a scan: confirm B1437, save the freeze frame and note any companion codes. Then inspect the wiring and connectors related to the ignition system, and verify the suspect component against live data before buying parts.

What are the symptoms of B1437?

Drivers most often notice: increased fuel consumption, loss of power and jerking, misfires under load or at idle, hard starting, especially in damp weather.

What is the most common cause of B1437?

The most common causes are: failed ignition coil or coil pack, faulty ignition control circuit in the ECM, worn spark plugs or wrong plug gap.

Will B1437 clear itself?

Sometimes B1437 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.

When your scanner pulls code B1437, it is telling you that the vehicle's control module has detected a specific electrical problem somewhere in the ignition system — specifically, the circuit that drives the wiper hi/low speed relay coil has shorted to ground. This places the fault squarely within the body electrical group as defined by the OBD2 standard. The control module constantly watches this circuit while the engine is running. If it sees voltage or resistance values that fall outside the normal operating window for more than the defined number of drive cycles, it logs B1437 and triggers the Check Engine Light. The freeze frame data stored alongside the code is particularly useful — it captures the exact engine speed, load, temperature, and vehicle speed the moment the fault occurred, giving you a precise starting point for your investigation.

To understand why B1437 matters, it helps to know how the affected circuit fits into the overall system. The wiper hi/low speed relay coil is responsible for controlling the relay that switches your windshield wipers between their high and low speed settings. When the coil circuit short-circuits to ground, the module loses proper control of that relay, and the wipers may stop working correctly or behave erratically. Because this circuit is monitored continuously, any interruption — whether from a wiring failure, a bad connector, or an internal short — will trigger B1437. The root cause can be as simple as a corroded connector or as involved as a failed relay coil inside the module itself.

Symptoms of B1437

The Check Engine Light illuminates and stays on
Windshield wipers fail to operate or operate at only one speed instead of switching between hi and lo
Wiper motor draws excessive current, potentially blowing fuses
Intermittent wiper operation that worsens in wet or humid conditions
Other body electrical functions may behave erratically if the underlying short affects shared wiring or the module ground
Scan tool shows B1437 as an active or pending code alongside any related electrical faults

Common causes of B1437

Shorted or chafed wiring in the wiper relay circuit, allowing the coil wire to contact ground
Corroded or loose connector at the wiper relay, wiper switch, or body control module
Failed wiper hi/low speed relay with an internal short in the coil windings
Water intrusion into the wiper motor housing or relay box, especially after car washes or heavy rain
Damaged printed circuit or solder joint inside the body control module affecting the relay driver circuit
Aftermarket alarm or accessory installation that was wired incorrectly into the wiper circuit

How to diagnose B1437

Connect an OBD2 scanner, confirm B1437 is stored, and record the freeze frame data. Note the engine speed, load, temperature, and vehicle speed captured at the moment the fault was detected — reproduce those conditions during your test drive to trigger the code consistently.
Visually inspect the entire wiper circuit wiring, paying close attention to the harness near the firewall, fender wells, and cowl area. Look for damaged insulation, broken strands, corrosion, and any signs that the wiring has rubbed against metal edges. Check the wiper relay connector and the connector at the wiper motor for bent pins, moisture, or greenish corrosion buildup.
Test the wiper relay coil resistance with a multimeter against the factory specification — typically between 50 and 150 ohms depending on the vehicle. An open circuit or a reading far outside spec indicates a failed relay coil. Swap the relay with a known-good unit if you have one available and observe whether the fault disappears.
Perform a voltage drop test along the ground path for the wiper relay circuit. A poor ground will cause the module to misinterpret the circuit state and set B1437 even when the wiring itself appears intact.
Check for TSBs (Technical Service Bulletins) specific to your make, model, and model year. Search by your VIN on the manufacturer's website or at nhtsa.gov — several body electrical codes like B1437 have known factory fixes, updated software calibrations, or revised wiring harness updates.
Clear the code, complete a full drive cycle that covers the conditions from the freeze frame data, and verify that B1437 does not return. If the code comes back, the fault is confirmed and present.

Repair options and costs

Replace the wiper hi/low speed relay — $40–$120 for the part, plus $50–$100 in labor if done at a shop. This is the most common and least expensive fix when the relay itself is at fault.
Repair damaged wiring or connectors in the wiper circuit — $80–$250, depending on how much wire needs to be replaced and whether the connector can be cleaned or must be replaced outright.
Replace the body control module or a faulty internal circuit board — $200–$600 for the module plus $75–$150 in programming labor, which is the most expensive scenario and should only be pursued after all other possibilities are ruled out.

How much does it cost to fix B1437?

The total bill hinges entirely on what component is actually at fault. Parts and labor for typical B1437 repair scenarios, priced at independent shop rates in USD, break down as follows:

Wiper relay replacement: $90–$220
Wiring or connector repair: $80–$250
Body control module replacement with programming: $275–$750

Across all scenarios, expect to spend anywhere from roughly $90 on the low end for a simple relay swap up to $750 on the high end if the body control module itself has failed. An accurate diagnosis before purchasing parts is the single most effective way to keep costs down — the priciest fix is rarely the right first step.

Can you drive with B1437?

Drive with caution. B1437 affects your windshield wipers, not the engine itself, so the vehicle remains mechanically operational. However, driving in rain or fog without functioning wipers creates an immediate safety hazard. Repair the fault before operating the car in wet conditions. There is no risk of catalytic converter damage with this particular code, but compromised visibility in bad weather is a serious concern.