Keypad/Illuminated Switch Circuit Open
The B1624 code indicates that the Body Control Module (BCM) or Generic Electronic Module (GEM) has detected an open circuit in the control output for the keyless entry keypad or illuminated switch panel illumination. The module monitors the output line to the keypad lamps; if the current is below the expected threshold (indicating a broken wire, disconnected connector, or burned-out filament in incandescent lamps), this DTC is stored.
1. Commonly Affected Makes
2. Most Common Causes
- Open circuit in the power or ground wiring to the keypad/switch panel
- Damaged, loose, or corroded keyless entry keypad (IAK) connector
- Burned-out keypad lamps (on models with incandescent bulbs)
- Internal failure of the output driver in the BCM/GEM
- Short to ground in the lamp control circuit (may be interpreted as open by the smart driver)
3. Symptoms You Will Notice
- Keypad or switch panel illumination inoperative
- Keyless entry keypad backlighting not working
4. Step-by-Step Diagnosis
Visually inspect the keypad/switch panel connector for damage, corrosion, or loose pins.
Check for battery voltage and ground at the keypad connector with the ignition on.
Test the keypad lamps for continuity; replace if open.
If wiring and lamps are good, suspect a faulty BCM/GEM output driver.
5. Frequently Asked Questions
Is it safe to drive?▼
Yes, this is a low-severity issue. The vehicle remains drivable, but the keypad illumination will not work, which may be inconvenient at night.
How much does it cost to fix?▼
Repair costs typically range from $50 to $200 for wiring or connector repairs, up to $300-$600 if the BCM/GEM needs replacement.