B1622 — Wiper Rear Low Limit Input Circuit Short To Ground

B1622 — Wiper Rear Low Limit Input Circuit Short To Ground. A fault in the body electrical system. The car is usually drivable while you plan the repair. Typical causes: blown fuse or failed relay, corroded or loose connectors, damaged wiring in door jambs or wet areas.

body electrical

Is it safe to drive?

Short-term driving is OK 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.

How to diagnose with an OBD scanner

Read the code and freeze frame Connect an OBD2 scanner, confirm B1622 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 body electrical system for damage, corrosion, chafing or poor contact.
Subsystem check Operate the affected function while watching its switch and motor PIDs in live data.
Subsystem check Inspect connectors and wiring at flex points (door jambs, tailgate hinges) — wires break there first.
Verify the repair Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm B1622 does not return.

Approximate repair cost

Repair cost depends on which component actually failed. Typical scenarios for B1622 (parts and labor, USD, independent shop rates): BCM repair or replacement: $300–$900; Repair wiring or connectors: $80–$250; Replace the switch or actuator: $120–$450. Overall, fixing B1622 usually costs between $80 and $900. An accurate diagnosis before buying parts saves money — the most expensive scenario is rarely the first one to check.

Common questions

Is it safe to drive with B1622?

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.

Will B1622 clear itself?

Sometimes B1622 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 much does it cost to fix B1622?

BCM repair or replacement — $300–$900; Repair wiring or connectors — $80–$250; Replace the switch or actuator — $120–$450. Exact cost depends on the root cause, your vehicle and local labor rates — a proper diagnosis is the cheapest first step.

How do I diagnose B1622 myself?

Start with a scan: confirm B1622, 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.

What is the most common cause of B1622?

The most common causes are: blown fuse or failed relay, corroded or loose connectors, damaged wiring in door jambs or wet areas.

When your vehicle's body control module detects a problem with the rear wiper system, it stores a specific diagnostic trouble code to help you pinpoint the issue. Code B1622 specifically indicates a "Wiper Rear Low Limit Input Circuit Short To Ground" condition. In plain terms, this means the module is seeing an unexpected electrical path to ground where one shouldn't exist in the circuit that monitors the rear wiper's lower parking position. The rear wiper system includes a motor, limit switch, and associated wiring, all under the supervision of the body control module or a dedicated rear wiper control unit. When the circuit that tells the module "the wiper is at rest position" shows a direct short to ground instead of the expected voltage signal, the module logs B1622.

Modern vehicles don't set a fault code after a single glitch. The control module requires the abnormal condition to appear consistently under specific operating parameters before it activates the check engine light or body system warning lamp. This deliberate threshold helps prevent false alarms from temporary electrical noise. When technicians pull B1622, they also retrieve the freeze frame data—a snapshot of engine load, RPM, coolant temperature, and vehicle speed at the moment the fault was recorded. This data is invaluable because it tells you exactly what conditions to recreate during testing. If the freeze frame shows the code was set while idling at operating temperature, you should replicate those exact circumstances when verifying the fault.

Common Symptoms of B1622

The most obvious sign of B1622 is the body system warning lamp illuminating on your dashboard. This is the module's way of alerting you that a fault exists in the rear wiper circuit. In most cases, your engine will continue running normally—this code affects the body electrical system, not the powertrain. The rear wiper itself will likely behave erratically or not function at all. You might notice the wiper failing to park in its correct low position after use, or it may not operate at all when activated. Intermittent operation is also common, where the wiper works sometimes but fails to respond in other instances. The rear windshield may not get the wiping action you expect, reducing visibility in rain or snow. Some vehicles with integrated rear wiper controls may also show symptoms in adjacent systems if the BCM is overwhelmed by multiple faults.

What Causes B1622

The most frequent culprit behind B1622 is corroded or loose electrical connectors in the rear wiper circuit. Moisture and road salt work their way into connectors over time, causing corrosion that increases resistance and creates intermittent short conditions. Wiring damage ranks second as a common cause, particularly in areas where wires flex repeatedly. Door jambs, tailgate hinges, and any location with moving wiring harness sections are vulnerable spots. A faulty body control module can also trigger B1622 if its internal circuits degrade or if it loses proper grounding. Blown fuses or failed relays in the wiper circuit interrupt power delivery and cause the module to see abnormal inputs. The rear wiper switch itself may fail, sending incorrect signals to the control module. Finally, the rear wiper motor or its internal limit switch can malfunction, producing the exact short-to-ground condition this code detects.

How to Diagnose B1622

Start by connecting a quality OBD2 scanner to your vehicle's diagnostic port and retrieve all stored codes. Confirm B1622 is present, then save the freeze frame data before clearing anything. This snapshot reveals engine conditions when the fault occurred. Next, look for any related diagnostic trouble codes that might point toward the root cause. Some B-series codes appear alongside each other when a shared component fails. Check manufacturer technical service bulletins using your vehicle identification number on the manufacturer website or NHTSA database—many body electrical faults have documented factory fixes or software updates. Perform a thorough visual inspection of the rear wiper circuit wiring and connectors, paying special attention to the motor connections, any wiring near the tailgate, and harness sections that pass through flex points. Operate the rear wiper while monitoring switch and motor data in your scanner's live data stream if supported. Finally, clear B1622, complete a full drive cycle that reproduces the freeze frame conditions, and verify the code does not return.

Repair Options and Costs

The cost to repair B1622 varies significantly depending on the actual failure point. Wiring harness repair or connector replacement typically runs between $80 and $250 for parts and labor at an independent shop. If the rear wiper switch or motor actuator requires replacement, expect to pay $120 to $450 depending on your vehicle and parts sourcing. The body control module itself is the most expensive component to address—BCM repair or replacement generally costs $300 to $900. Most shops charge $75 to $150 per hour for labor, so connector cleaning or minor wiring repairs fall at the lower end of these ranges while BCM replacement with programming lands at the higher end.

Can You Drive With B1622?

B1622 is generally classified as a short severity fault, meaning you can continue driving without immediate concern for vehicle damage. The rear wiper won't function properly, which reduces visibility in wet conditions but doesn't affect your ability to operate the car safely in dry weather. The engine and transmission operate completely normally since this code relates solely to body electrical functions. However, consider having the issue diagnosed soon, especially if you frequently encounter rain or if your vehicle's rear visibility is already compromised. The underlying cause—such as water intrusion or wiring damage—could worsen over time and potentially affect other systems.