Trunk or Glovebox Light Stuck On
A trunk or glovebox light stuck on can drain the battery while the vehicle is parked. The usual cause is a misadjusted latch switch, stuck light switch, damaged wiring, or an aftermarket accessory keeping that circuit awake.
Can I Drive?
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Most Likely Causes
- 1
Battery has low reserve capacity
An aged or sulfated battery may test above 12 volts but still fail under load or cold starts.
- 2
Parasitic draw after modules should be asleep
A light, module, relay, or accessory can keep pulling current with the car off.
- 3
Corroded or loose terminal connection
Resistance at the terminal or ground can reduce cranking and charging even with a good battery.
- 4
Aftermarket accessory wired to constant power
Radios, dashcams, amps, alarms, trackers, or remote starts can stay awake if wired incorrectly.
How to Diagnose It
- 1
Load-test the battery
Test cold-cranking ability and reserve capacity, not just open-circuit voltage.
Tool: Battery tester
- 2
Measure parasitic draw after sleep time
Wait for modules to sleep, then measure draw in series or use an amp clamp.
Tool: Multimeter or low-amp clamp
- 3
Inspect lights and accessories after shutdown
Check trunk, glovebox, vanity, underhood lights, chargers, and aftermarket devices.
Tool: Flashlight
How to Fix It
Replace a battery that fails load testing
Use the correct group size and CCA rating for the vehicle.
Repair the draw source
Repair the stuck relay, light switch, module, or accessory wiring that remains active.
Clean and tighten terminals and grounds
Remove corrosion and verify solid connections at battery, engine block, and chassis.
Mistakes to Avoid
- Do not replace the battery before checking whether the trunk, glovebox, vanity, or underhood light stays on after the vehicle is closed.
- Do not perform a parasitic draw test with doors open or modules awake unless the latch switches are properly simulated.
- Do not ignore an aftermarket alarm, dashcam, charger, or remote-start wiring tied into the same always-on circuit.