B1373: Illuminated Entry Relay Short to Battery
The B1373 code indicates a short to battery positive voltage in the control circuit of the illuminated entry relay. This relay powers the courtesy lights, footwell lights, and welcome lighting when the doors are unlocked or opened. The Body Control Module (BCM) monitors the relay control circuit for electrical faults. When it detects an unexpected voltage or abnormally low resistance indicating a short to battery positive, it sets code B1373. This typically causes the entry lighting system to malfunction or interior lights to remain off when doors are opened.
1. Commonly Affected Makes
2. Most Common Causes
- Faulty illuminated entry relay stuck in the closed position
- Short to battery positive voltage in the relay control circuit wiring
- Damaged, corroded, or bent terminals in the relay or BCM connector
- Faulty Body Control Module (BCM) with internal circuit driver failure
- Moisture or water intrusion causing voltage bridging in circuit connections
3. Symptoms You Will Notice
- Interior courtesy lights do not turn on when doors are opened
- Welcome lighting (puddle lights, footwell lights) inoperative
4. Step-by-Step Diagnosis
Check for technical service bulletins (TSBs) related to B1373 for your vehicle
Inspect the illuminated entry relay and its connector for damage, corrosion, or bent pins
Test the relay control circuit for short to battery positive using a multimeter
Check for water intrusion or moisture in the BCM and relay connectors
If all else is normal, test the BCM output or replace the BCM as a last resort
5. Frequently Asked Questions
Is it safe to drive?▼
Yes, it is generally safe to drive. The code only affects interior lighting functions, not vehicle drivability.
How much does it cost to fix?▼
Repair costs typically range from $100 to $400, depending on whether the relay, wiring, or BCM needs replacement.