B1664 — Seat Driver Rear Up/Down Motor Stalled #

Note: The wording of this DTC (Diagnostic Trouble Code) may vary depending on the vehicle manufacturer (OEM). Below are known variations for B1664:

• Ford: Seat Driver Rear Up/Down Motor Stalled
• GM: Driver Seat Rear Height Adjust Motor Stalled
• Chrysler: Driver Seat Height Rear Motor Circuit Stalled

Summary of Code B1664 #

The B1664 DTC points to a malfunction with the driver’s seat rear up/down motor. This code is typically set when the vehicle’s seat control module detects that the motor responsible for adjusting the rear of the driver’s seat up or down is not responding as expected—specifically, it is considered “stalled”, meaning it’s not moving despite receiving power. This could be due to a mechanical jam, electrical issue, or even a faulty seat switch. As a “B” (body) code, B1664 does not generally affect engine performance or safety systems but can impact comfort and adjustability for the driver. While not immediately critical, prompt diagnosis is recommended to ensure continued comfort and to prevent further electrical issues.

Common Symptoms for Code B1664 #

When B1664 is stored, you’ll typically notice that the rear portion of the driver’s seat won’t move either up or down when using the seat adjustment controls. The issue is usually isolated to the rear height function, while other seat adjustments might remain operational. In rare cases, you might hear a clicking or humming from the seat motor, or the seat may be stuck in an uncomfortable position.

• Driver’s seat rear height adjustment does not work
• Clicking, humming, or no sound at all from seat motor area
• Seat stuck at lowest or highest rear position
• Possible intermittent seat movement
• Other seat functions (forward/back, tilt, etc.) work normally
• Sometimes, a seat control warning may appear on the dash (varies by OEM)

Probable Causes for B1664 (in order of likelihood) #

B1664 is usually triggered by an interruption in the normal movement of the driver’s seat rear up/down motor. The causes can range from simple to complex, but most often relate to mechanical binding or electrical issues.

1. Obstructed or jammed seat track (object wedged in track or seat mechanism)
2. Faulty seat rear up/down motor (worn brushes, internal failure)
3. Defective seat adjustment switch (contacts not closing/opening properly)
4. Broken or disconnected wiring/connectors at the seat or motor
5. Fault in the seat control module (less common, usually after other causes are ruled out)

Step-by-Step Diagnostic for B1664 #

Diagnosing B1664 requires a logical, methodical approach to rule out the most common and accessible causes before considering expensive replacements. Here’s a practical step-by-step process:

1. Visual inspection: Check under the seat for any objects or debris that could block the seat movement. Remove any obstructions found.
2. Operate all seat functions: Test each seat adjustment. If only the rear up/down is affected, proceed; if others fail, suspect a more general electrical issue.
3. Listen for motor noise: While pressing the up/down switch, listen for humming or clicking, which may indicate a jammed but powered motor.
4. Check seat switch operation: Use a multimeter to verify that the switch is sending the correct signal to the motor when pressed.
5. Inspect wiring and connectors: Look for loose, corroded, or damaged connectors/wiring at the seat base and motor.
6. Direct power test: If accessible, apply 12V directly to the motor terminals (with care) to check if the motor itself is seized or operational.
7. Scan for additional codes: Use a scan tool to check if related seat or body control codes are present, which may help focus your diagnosis.
8. Module test (if equipped): On some vehicles, the seat control module can be checked with OEM diagnostic software for output commands and faults.

Possible Repairs for B1664 #

Once you’ve pinpointed the root cause, the appropriate repair will usually fall under one of these categories. Always verify the fix by clearing the code and ensuring full seat function.

• Remove obstruction: Clear any debris or objects from seat track or mechanism.
• Replace faulty seat rear up/down motor: Install new OEM or equivalent motor if the original is seized or not responding.
• Repair or replace seat adjustment switch: If the switch fails continuity testing, replace it.
• Repair wiring/connectors: Fix or replace any damaged wires or corroded connectors between the switch, motor, and seat module.
• Replace seat control module: Only after confirming all other components are good; may require programming (check OEM procedure).

Is It Safe to Drive with Code B1664? #

Yes, you can generally continue to drive with code B1664 present, as it does not affect critical vehicle functions like braking, steering, or engine performance. However, if the seat is stuck in an uncomfortable or unsafe position—such as too low or too far back—it could interfere with your ability to drive safely. Addressing the issue promptly is recommended for comfort and to avoid further electrical problems.

Vehicles Most Commonly Affected by B1664 #

B1664 is most commonly encountered on vehicles with power-adjustable seats, particularly those from North American OEMs. While not exclusive, the following brands and models are most likely to show this code:

• Ford F-Series (F-150, F-250, etc.)
• Chevrolet Silverado and GMC Sierra
• Chrysler/Dodge minivans and sedans with power seats
• Lincoln and Cadillac luxury models
• Some Honda/Acura and Toyota/Lexus vehicles with advanced seat memory modules

Common Mistakes & Best Practices with B1664 #

While B1664 is straightforward, there are a few pitfalls to avoid and smart strategies to follow for an efficient repair.

• Overlooking physical obstructions: Always check for objects under the seat before suspecting electrical issues.
• Assuming the motor is bad without testing: Use a direct power test to confirm a failed motor before replacement.
• Ignoring wiring/connectors: Corroded or loose connections are a frequent cause—don’t skip this step.
• Replacing modules unnecessarily: The seat control module is rarely the culprit; exhaust all other possibilities first.
• Not clearing codes after repair: Always clear the code and verify seat operation before finishing the job.

Quick FAQ for B1664 #

Here are answers to some of the most common questions about B1664:

• Q: Can I manually move the seat if the motor is stalled?
  A: Most power seats cannot be adjusted manually if the motor is jammed. Forcing the seat can cause further damage. It’s best to repair the root issue.
• Q: Will disconnecting the battery reset the code?
  A: Disconnecting the battery may temporarily clear the code, but it will return if the underlying problem persists. Proper diagnosis and repair are needed.