If your vehicle is showing dashboard clock keeps losing time or resetting to 12:00, here are the most likely causes and the parts you'll need to fix each one.
An aging battery may lack the capacity to maintain sufficient voltage while the starter motor is cranking. This sudden voltage drop cuts power to the clock's memory circuit, causing it to reset to 12:00.
A poor connection at the battery posts can cause momentary power interruptions, especially over bumps or during engine startup. This is a frequent issue if the terminals were not tightened properly after recent under-hood work.
The clock relies on a constant-power fuse (often labeled 'memory', 'backup', or 'room') to keep time when the ignition is off. If this fuse is blown, loose, or was put back into the wrong slot, the clock will reset every time you turn the car off.
If the alternator is undercharging, the battery voltage will slowly deplete while driving. This low system voltage can cause sensitive electronics like the clock to lose their memory.
The BCM manages interior electronics and power distribution. An internal software glitch or hardware failure can cause it to intermittently drop power to the dashboard clock and other memory-dependent accessories.