B1589: Autolamp Delay Circuit Short to Battery
The B1589 code indicates a short to battery voltage in the Autolamp Delay Increase circuit. This system controls how long the exterior lights stay on after the vehicle is turned off. When the Body Control Module (BCM) detects an abnormally high voltage on a circuit that should only see ground or a low reference signal, it sets this code. The issue is often caused by the control circuit wiring rubbing against a power feed, allowing battery voltage into a low-voltage signal pin.
1. Commonly Affected Makes
2. Most Common Causes
- Short to voltage in the Autolamp control circuit harness
- Wiring damaged from chafing or excessive heat
- Internal failure of the Body Control Module (BCM)
- Defective autolamp delay switch
- Corroded electrical connections or bent pins in connectors
3. Symptoms You Will Notice
- Exterior lights staying on longer than normal or not turning off
- Autolamp delay adjustment not working
4. Step-by-Step Diagnosis
Check for technical service bulletins (TSBs) related to the BCM or autolamp system
Inspect the autolamp delay switch and its wiring for damage or corrosion
Test the control circuit for short to battery voltage using a multimeter
Check BCM connectors for bent, corroded, or pushed-out pins
If wiring and switch are okay, suspect a faulty BCM and perform further module testing
5. Frequently Asked Questions
Is it safe to drive?▼
Yes, the severity is low. The vehicle remains drivable, but the autolamp delay feature may not work correctly. It's advisable to have it diagnosed soon to prevent battery drain.
How much does it cost to fix?▼
Depending on the cause, repair costs typically range from $100 to $400. A simple wiring repair may be under $150, while BCM replacement can be $300–$400 including labor.