What Does B1729 Mean?
This code indicates the Body Control Module (BCM) has detected a malfunction in the electrical circuit controlling the driver's seat rear-down adjustment switch. The BCM monitors the switch input and has identified an open circuit, short to ground, short to power, or internal switch failure that prevents proper signal transmission. This affects the power seat adjustment system's ability to lower the rear portion of the driver's seat.
Common Causes
40%
Faulty driver seat rear-down switch with internal contact failure or mechanical wear
30%
Damaged or corroded wiring harness between seat switch and BCM, including connector pin corrosion
20%
Failed seat control module or seat memory module with internal circuit fault
10%
Blown fuse or poor ground connection in the seat power circuit
Diagnostic Steps
1
Step 1: Perform visual inspection of the driver seat switch assembly for physical damage, liquid intrusion, or obvious wear; operate the rear-down switch and listen/feel for proper mechanical click action
2
Step 2: Using a digital multimeter, check voltage supply at the seat switch connector (typically 5V or 12V reference); verify ground continuity with engine off using resistance measurement (should be less than 1 ohm to chassis ground)
3
Step 3: With switch connector attached and key on, backprobe the switch signal wire while activating the rear-down switch; voltage should change from reference voltage to ground or vice versa depending on manufacturer design
4
Step 4: If switch operates correctly, measure resistance through the wiring harness from switch connector to BCM/seat module connector (should be less than 5 ohms); inspect all connectors for bent pins, corrosion, or moisture intrusion
5
Step 5: Test the switch assembly independently by disconnecting it and using an ohmmeter to verify continuity changes when the rear-down button is pressed (consult manufacturer specifications for expected resistance values)
6
Step 6: Clear codes, perform seat function test using the rear-down switch, and verify code does not return; if code persists after wiring and switch checks, suspect seat control module failure
Estimated Repair Cost
$75 - $450
Parts + labor, varies by vehicle and location
This code indicates the Body Control Module (BCM) has detected a malfunction in the electrical circuit controlling the driver's seat rear-down adjustment switch. The BCM monitors the switch input and has identified an open circuit, short to ground, short to power, or internal switch failure that pre...
The most common cause of B1729 (Seat Driver Rear Down Switch Circuit Failure) is: Faulty driver seat rear-down switch with internal contact failure or mechanical wear
Typical repair costs for B1729 range from $75 to $450, depending on the vehicle, location, and whether you do it yourself or go to a shop.
This code does not affect vehicle safety or drivability and the vehicle is safe to operate. The only impact is reduced comfort and convenience as the rear portion of the driver's seat cannot be adjusted downward using the power seat controls.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1729 to identify the root cause.
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Quick Info
Category
Body
System
Power Seat Adjustment System
Difficulty
Type
Manufacturer
Recommended Tools
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