B1736 — Mirror Driver Vertical Switch Circuit Short To Ground #

Note: The code label may vary depending on the vehicle manufacturer.

• B1736: Driver Mirror Vertical Switch Circuit Short to Ground (Ford, Lincoln, Mercury)
• B1736: Door Mirror Switch Down Input Circuit Short to Ground (General Motors/Chevrolet)
• B1736: Driver’s Side Mirror Vertical Adjustment Circuit Low (Chrysler, Dodge, Jeep)

Overview of Code B1736 #

The B1736 diagnostic trouble code (DTC) indicates that the vehicle’s onboard computer has detected a short to ground in the driver’s side mirror vertical adjustment switch circuit. In simpler terms, it means there is an electrical fault—specifically, an unintended path to ground—in the wiring or switch that controls the up and down movement of the driver’s mirror. This code is set when the control module (often called the Body Control Module or BCM) receives an abnormal voltage signal from the mirror control switch circuit. While this issue does not usually compromise overall driving safety, it can affect the driver’s ability to adjust the mirror properly, potentially limiting visibility and comfort. Recognizing and addressing this code ensures your vehicle’s mirror system functions as intended.

Common Symptoms for Code B1736 #

Symptoms associated with the B1736 code are typically focused on the malfunction of the driver’s side mirror controls. Drivers may notice the mirror does not move vertically or responds unpredictably. In some cases, you may see a warning light on the dashboard or receive a message if your vehicle is equipped with an advanced information display.

• Driver’s side mirror will not move up or down when using the adjustment switch
• Erratic or involuntary movement of the mirror
• Mirror may be stuck in one position
• Warning light on dashboard (in some vehicles)
• Possible inoperative memory or auto-tilt functions for the driver’s mirror

Probable Causes for Code B1736 #

A variety of factors may cause a short to ground in the driver’s mirror vertical switch circuit. Most often, these are related to wiring issues, switch failures, or problems with the mirror actuator itself. Here is a prioritized list of the most common culprits:

1. Damaged or frayed wiring in the mirror control circuit making contact with the vehicle chassis (ground)
2. Faulty driver’s mirror adjustment switch (internal short or failure)
3. Defective mirror motor/actuator with internal electrical fault
4. Corroded or loose electrical connectors at the switch, mirror, or body control module
5. Water intrusion in the door panel causing shorts in the wiring harness
6. Faulty Body Control Module (BCM) (rare, but possible if all else checks out)

Step-by-Step Diagnosis for Code B1736 #

Diagnosing a B1736 code involves systematically checking each component in the mirror adjustment circuit, starting with the most likely sources of trouble. Here’s how a professional technician would approach it:

• 1. Verify the code: Use a scan tool to confirm the B1736 code is present and review any related codes.
• 2. Inspect the mirror switch: Check the driver’s mirror adjustment switch for visible damage, wear, or moisture.
• 3. Examine wiring and connectors: Remove the door panel and carefully inspect the wiring harness and connectors for fraying, pinching, or signs of shorting to ground.
• 4. Test the mirror motor: Apply power and ground directly to the mirror motor’s vertical adjustment terminals to see if it operates normally.
• 5. Check for water damage: Look for any signs of water intrusion inside the door that could cause electrical shorts.
• 6. Test continuity and short-to-ground: Using a multimeter, perform continuity and short-to-ground tests on the suspect wiring.
• 7. Inspect BCM operation: If all previous steps are inconclusive, consider checking the Body Control Module for faults (consult OEM procedures).

Possible Repairs for Code B1736 #

Once you’ve pinpointed the cause of the B1736 code, repairs are generally straightforward. Always disconnect the vehicle’s battery before working on electrical components to prevent further damage or accidental airbag deployment.

• Repair or replace damaged wiring in the mirror switch circuit
• Replace the driver’s mirror adjustment switch if found defective
• Replace the mirror motor/actuator if it fails operational tests
• Clean and secure electrical connectors; replace if corroded
• Address and seal any water leaks inside the door panel
• Replace or reprogram the Body Control Module (BCM) if all other causes are ruled out (rare)

Is It Safe to Drive with Code B1736? #

Yes, but with limitations. While the B1736 code does not directly affect your vehicle’s drivability or critical safety systems, it can hinder your ability to properly adjust the driver’s side mirror. This may reduce your field of vision and potentially create blind spots, especially if more than one driver uses the vehicle or if the mirror is stuck in an unsafe position. For optimal safety and comfort, it’s best to address the issue promptly.

Vehicles Most Commonly Affected by Code B1736 #

This code is most often reported on vehicles with power-adjustable mirrors, especially those with memory or auto-tilt features. The following models frequently appear in technical bulletins and forums related to B1736:

• Ford F-Series trucks (F-150, F-250, etc.)
• Ford Explorer, Expedition, and Lincoln Navigator
• Chevrolet Silverado and GMC Sierra
• Chevrolet Tahoe and Suburban
• Chrysler Town & Country, Dodge Grand Caravan
• Jeep Grand Cherokee
• Various luxury vehicles (Mercedes-Benz, BMW, Audi) with advanced mirror features

Common Mistakes & Best Practices for Code B1736 #

Technicians and DIYers sometimes overlook key steps when addressing a B1736 code. Awareness of these pitfalls and following best practices will help ensure a lasting repair.

• Assuming the mirror switch is always to blame—often, wiring issues are the root cause.
• Neglecting to check for water damage or corrosion inside the door panel.
• Failing to use a wiring diagram to trace the circuit properly.
• Replacing expensive components like the BCM before checking basic wiring and connectors.
• Not clearing the code after repair—always confirm with a scan tool that the issue is resolved.

Quick FAQ for Code B1736 #

Here are answers to some of the most common questions drivers and technicians have about the B1736 code:

• Q: Can a blown fuse cause the B1736 code?
  A: Not directly. A blown fuse would disable the entire mirror adjustment system rather than cause a short-to-ground code. However, if a short circuit caused the fuse to blow, both issues may need attention.
• Q: Will this code affect my mirror’s memory settings?
  A: Yes, if the vertical adjustment is inoperative, memory and auto-tilt functions related to that axis may not work correctly.
• Q: Is this a dealer-only repair?
  A: Not usually. Most independent repair shops and experienced DIYers can address this with standard electrical troubleshooting tools and access to wiring diagrams.