B1588 Autolamp Delay Circuit Open
The B1588 code indicates an open circuit in the Autolamp delay function, which keeps the headlights on for a preset time after the ignition is turned off. The Body Control Module (BCM) detects a break in the control or feedback circuit responsible for adjusting or extending this timer. The loss of continuity prevents the BCM from verifying the delay circuit status, causing the delayed headlight shutdown feature to become inoperative or stuck at a default value.
1. Commonly Affected Makes
2. Most Common Causes
- Open circuit in the Autolamp system wiring
- Corroded or bent pins in the BCM connector
- Faulty Autolamp control switch (delay rheostat)
- Blown lighting system fuse
- Internally damaged Body Control Module (BCM)
3. Symptoms You Will Notice
- Headlights do not stay on after turning off the ignition
- Headlights stay on indefinitely or turn off immediately
4. Step-by-Step Diagnosis
Check for blown fuses related to the lighting system
Inspect the Autolamp delay switch and wiring for continuity
Examine the BCM connector for corrosion or bent pins
Test the BCM for internal faults if all other components check out
5. Frequently Asked Questions
Is it safe to drive?▼
Yes, it is safe to drive. The issue only affects the automatic headlight delay feature; manual headlight operation remains functional.
How much does it cost to fix?▼
Repair costs typically range from $50 to $200 for wiring or switch repairs, up to $500–$800 if BCM replacement is needed.