B1622 — Wiper Rear Low Limit Input Circuit Short To Ground #

Note: The code description can vary depending on the manufacturer (OEM). Always verify with your vehicle’s specific documentation for precise terminology.

• Rear Wiper Low Limit Circuit Shorted to Ground (Ford)
• Rear Wiper Limit Switch Circuit Low Short to Ground (Chrysler)
• Wiper, Rear, Low Limit Switch Input Circuit Grounded (Mazda)

Summary of code B1622 #

The B1622 Diagnostic Trouble Code (DTC) signals an electrical problem in the rear wiper system, specifically in the “low limit input circuit.” This circuit monitors the position of the rear wiper arm to help the control module (often called the Body Control Module or BCM) determine if the wiper is at its parked (resting) position. If the BCM detects that this circuit is “shorted to ground” — meaning an unintended electrical path is connecting the circuit directly to the vehicle’s chassis ground — it sets the B1622 code and may disable rear wiper operation to prevent further issues. This malfunction can lead to erratic or nonfunctional rear wiper performance. Drivers may notice that their rear wiper does not return to its proper resting position, or fails to operate altogether.

Common symptoms for code B1622 #

If your vehicle’s computer triggers the B1622 code, you’ll likely experience issues related to rear wiper operation. These symptoms can range from minor annoyances to significant visibility problems during bad weather. Here’s what you might notice:

• Rear wiper fails to operate or respond to the switch
• Wiper arm stops in an unusual position (not parked correctly)
• Erratic or intermittent rear wiper movement
• Rear wiper fuse may blow repeatedly
• Warning lights or messages on the dash related to wiper system

Probable causes for code B1622 #

Several factors can trigger the B1622 code, but some causes are more common than others. This list is ordered from most to least likely:

1. Short circuit to ground in the rear wiper low limit switch wiring
2. Damaged or corroded rear wiper limit switch (position sensor)
3. Faulty or stuck rear wiper motor assembly
4. Fault in the BCM or rear wiper control relay
5. Water intrusion or corrosion in the rear hatch electrical connector
6. Poor ground connection at the body or rear hatch

Step-by-step diagnosis for code B1622 #

Diagnosing a B1622 code requires a methodical approach to avoid unnecessary parts replacement. Here’s a systematic checklist:

• Read all stored codes with a scan tool and clear them. See if B1622 returns immediately or after activating the rear wiper.
• Visually inspect the rear wiper harness and connector for signs of fraying, pinching, or corrosion.
• Check the rear wiper fuse and relay for proper operation.
• Using a multimeter, test for continuity between the low limit switch circuit and ground. There should be no continuity unless the switch is in the parked position.
• If shorted to ground is confirmed, disconnect the wiper motor and check again — helps isolate wiring vs. motor/switch fault.
• Inspect the rear wiper motor and limit switch assembly for water damage or mechanical sticking.
• If the wiring and switches test fine, check BCM inputs and outputs related to the rear wiper circuit per OEM wiring diagrams.

Possible repairs for code B1622 #

Depending on what the diagnosis uncovers, repairs for B1622 can range from simple wiring fixes to component replacement. Here are the most common solutions:

• Repair or replace damaged rear wiper harness sections, especially if pinched or corroded
• Replace a faulty or water-damaged rear wiper limit switch (usually part of the wiper motor assembly)
• Replace the rear wiper motor if the internal switch or circuitry is shorted
• Clean and secure all rear hatch electrical connectors and ground points
• Replace the rear wiper relay if stuck or malfunctioning
• In rare cases, reprogram or replace the BCM if it has a confirmed internal fault

Can I drive with code B1622? #

Yes, but with limitations. The B1622 code itself does not directly affect core vehicle safety systems. However, if you regularly rely on your rear wiper for visibility — especially in rain, snow, or muddy conditions — you should address the problem as soon as possible. Reduced rear visibility can compromise your safety and that of others, particularly in bad weather or during highway driving.

Vehicles most commonly affected by code B1622 #

While B1622 can appear on many vehicles, it is most frequently reported on models where the rear wiper system uses a low limit switch for park position feedback. Based on field data and service bulletins, the following vehicles are commonly affected:

• Ford Escape, Edge, and Explorer (various years)
• Chrysler Town & Country, Dodge Grand Caravan
• Mazda CX-5 and CX-7
• Lincoln MKX, MKC
• Jeep Grand Cherokee (select models with rear wiper feedback switch)

Common mistakes & best practices for B1622 #

It’s easy to make assumptions with electrical faults like B1622. Rushed troubleshooting can waste time and money. Here’s what to avoid, and what to do instead:

• Mistake: Replacing the wiper motor before checking wiring — always test the circuit for shorts first.
• Mistake: Ignoring water intrusion in the rear hatch, which often causes corrosion and shorts.
• Mistake: Overlooking the BCM’s role — it’s rare, but possible for the module to be at fault after ruling out wiring and switches.
• Best practice: Use the OEM wiring diagrams to trace the exact path of the low limit input circuit.
• Best practice: If unsure, use a scan tool with live data to monitor rear wiper position input signals.

Quick FAQ for code B1622 #

Here are some rapid answers to common questions about this code:

• Q: Can a blown fuse cause B1622?
  A: Yes, if the fuse blows due to a short circuit, the BCM may detect a grounded input and set B1622.
• Q: Do I need to replace the entire wiper motor if only the limit switch is bad?
  A: On many vehicles, the limit switch is integrated into the wiper motor assembly and not sold separately. However, check your OEM parts catalog, as some models allow separate switch replacement.