B1625: Lamp Keypad Output Short to Battery
Diagnostic trouble code B1625 indicates a short to battery voltage in the lamp keypad output circuit. This Ford-specific code is set by the interior lighting control module (often the GEM or body control module) when it detects battery voltage on the lamp keypad output line when it should be low. The lamp keypad controls courtesy, reading, and map lights. A short to battery can damage the module or cause unintended light operation.
1. Commonly Affected Makes
2. Most Common Causes
- Short to battery voltage in the lamp keypad wiring harness
- Internally shorted lamp keypad switch assembly
- Corroded or bent pins in the lighting module connector causing contact with power
- Faulty interior lighting control module (GEM or body control module) with a shorted output driver
- Aftermarket electrical accessories or modifications interfering with the lighting circuit
3. Symptoms You Will Notice
- Interior lights (courtesy, reading, map) staying on continuously or operating erratically
- Lamp keypad buttons unresponsive or causing incorrect light behavior
- Blown fuse for interior lighting circuit
- Battery drain if lights remain on
4. Step-by-Step Diagnosis
Check for technical service bulletins (TSBs) related to B1625 for the specific vehicle model.
Visually inspect the lamp keypad wiring harness for damage, chafing, or contact with metal surfaces.
Test the lamp keypad output circuit for voltage with the keypad disconnected; if voltage is present, trace the short to battery.
Inspect the lighting module connector for corrosion, bent pins, or moisture.
If wiring and connector are okay, substitute a known-good lamp keypad to rule out internal short.
If problem persists, test the lighting module output driver; replace module if faulty.
5. Frequently Asked Questions
Is it safe to drive?▼
Yes, severity is low. The vehicle is generally safe to drive, but interior lights may not work correctly or may stay on, potentially draining the battery. Have it diagnosed soon.
How much does it cost to fix?▼
Repair costs vary widely: a simple wiring repair may cost $50-$150, while replacing a lamp keypad assembly runs $100-$250. If the lighting module needs replacement, expect $300-$600 including labor.