B1302: Accessory Delay Relay Circuit Fault
The B1302 code indicates that the Body Control Module (BCM) or Generic Electronic Module (GEM) has detected a fault in the control circuit (coil side) of the accessory delay relay. This relay keeps power flowing to accessories like power windows, radio, and sunroof for a short time after the ignition is turned off. The fault is triggered when the module detects an open circuit, short to ground, or short to battery voltage in the relay coil circuit during self-test or activation.
1. Commonly Affected Makes
2. Most Common Causes
- Faulty accessory delay relay (open or shorted coil)
- Damaged wiring between the BCM/GEM and the relay (open circuit or short to ground/battery)
- Loose, corroded, or pushed-out terminals at the relay or BCM/GEM connector
- Internal BCM/GEM output driver failure
3. Symptoms You Will Notice
- Accessories like power windows, radio, or sunroof may not work after ignition is turned off
- Accessories may work intermittently or not at all
4. Step-by-Step Diagnosis
Check for technical service bulletins (TSBs) related to B1302 for the specific vehicle
Inspect the accessory delay relay and its connector for corrosion, damage, or loose terminals
Test the relay coil resistance and verify proper voltage and ground at the relay control circuit
Check wiring between the BCM/GEM and relay for opens or shorts
If all wiring and relay are good, suspect a faulty BCM/GEM output driver
5. Frequently Asked Questions
Is it safe to drive?▼
Yes, the vehicle is generally safe to drive, but you may lose convenience features like delayed accessory power. The issue does not affect engine or safety systems.
How much does it cost to fix?▼
Repair costs typically range from $100 to $400, depending on whether the relay, wiring, or BCM/GEM needs replacement. Diagnostic fees may add $50–$100.