When your 2021 Infiniti Q50's trunk ajar warning light stays on constantly despite the trunk being securely closed, you're dealing with a sensor or switch issue. This false warning is annoying and can drain your battery if the trunk light stays on as a result.
How Trunk Status is Detected
The Q50 uses a trunk ajar switch, typically part of the trunk latch assembly, to detect whether the trunk is open or closed. When the trunk closes, the switch changes state and signals "closed" to the body control module. A constantly on warning means this switch is reporting "open" regardless of actual trunk position.
Causes of Constant Ajar Warning
The light stays on due to: failed trunk ajar switch stuck in the open position, misaligned trunk latch or striker preventing proper switch engagement, wiring damage creating an open circuit, corroded switch contacts, a bent trunk that doesn't fully engage the switch, or body control module issues misinterpreting the signal.
Consequences of Ignoring It
Beyond annoyance: the trunk interior light may stay on, draining the battery. The vehicle alarm may be affected (won't arm with trunk "open"). Keyless operation may be impacted. It's more than a cosmetic problem.
Diagnostic Steps
Firmly push on the closed trunk to verify it's fully latched. Inspect latch and striker alignment. Locate the ajar switch on the latch assembly and try manually depressing it while watching the warning light. Check wiring to the switch for damage. Use a scan tool to monitor the trunk switch input signal.
Repair Solutions
Latch adjustment if alignment is preventing switch engagement. Switch replacement if it's failed in the open position. Wiring repair for damaged circuits. Striker adjustment to ensure proper latch engagement depth. Latch assembly replacement if the switch is integrated and failed.