B1333: Decklid Ajar Switch Circuit Short to Battery
The B1333 code indicates that the Body Control Module (BCM) has detected a short to battery voltage (B+) in the decklid ajar switch signal circuit. This prevents the BCM from correctly determining whether the trunk or rear hatch is open or closed, as the circuit remains permanently high (12V).
1. Commonly Affected Makes
2. Most Common Causes
- Internal short to power within the decklid ajar switch
- Chafed or pinched wiring in the switch signal circuit contacting a B+ wire
- Damaged, corroded, or bridged terminals in the switch or BCM connector
- Internal BCM failure in the input pull-down driver for that circuit
3. Symptoms You Will Notice
- Trunk or rear hatch ajar warning light stays on constantly
- Interior lights may not operate correctly when trunk is opened
- Remote trunk release may not function
- Possible battery drain if interior lights stay on
4. Step-by-Step Diagnosis
Scan for B1333 and check for additional related codes
Visually inspect the decklid ajar switch and its wiring for damage or corrosion
Disconnect the switch and measure voltage at the signal wire; if still 12V, suspect a short to B+ in the wiring or BCM
Check for continuity between the signal wire and B+ with the switch disconnected
If wiring is intact, test the switch for internal short by measuring resistance between its terminals
If all else passes, suspect a faulty BCM and perform a BCM self-test or replacement
5. Frequently Asked Questions
Is it safe to drive?▼
Yes, it is generally safe to drive with code B1333, but the trunk ajar warning may be inaccurate and interior lights may stay on, potentially draining the battery. Have it diagnosed soon.
How much does it cost to fix?▼
Repair costs typically range from $100 to $400, depending on whether the issue is a simple switch replacement ($50-$150) or wiring repair ($100-$300). BCM replacement can exceed $500.