B1735: Driver Mirror Vertical Position Switch Short to Battery
Diagnostic trouble code B1735 indicates a short to battery positive voltage in the driver side mirror vertical position switch circuit. This code is specific to Ford Motor Company and its associated brands. The mirror control module detects an abnormally high voltage on the switch circuit that controls the vertical movement of the driver's mirror, typically caused by wiring contacting a constant positive voltage source. The power mirror system uses momentary switches that send specific voltage signals to the mirror control module when activated; a short to battery prevents proper interpretation of these signals.
1. Commonly Affected Makes
2. Most Common Causes
- Damaged or worn mirror switch wiring making contact with battery positive voltage
- Faulty mirror control switch with internal short circuit
- Moisture or corrosion in the switch or mirror module connector
- Incorrect or bypassed fuse allowing overvoltage in the circuit
- Internal failure of the mirror control module (less common)
3. Symptoms You Will Notice
- Driver side mirror does not move up or down
- Mirror may move erratically or in the wrong direction
- Mirror may be stuck in one position
4. Step-by-Step Diagnosis
Visually inspect the mirror switch wiring and connector for damage, corrosion, or contact with positive voltage sources.
Test the mirror switch for internal shorts using a multimeter; replace if faulty.
Check the mirror control module connector for moisture or corrosion; clean if needed.
Verify the correct fuse is installed and not bypassed; replace if incorrect.
If all else fails, test the mirror control module per service manual; replace if defective.
5. Frequently Asked Questions
Is it safe to drive?▼
Yes, the vehicle is safe to drive. The issue only affects the driver side mirror vertical adjustment, which is a convenience feature. However, you may need to manually adjust the mirror.
How much does it cost to fix?▼
Repair costs typically range from $50 to $200 for switch replacement or wiring repair, and up to $400 if the mirror control module needs replacement.