Digital clock has gone nuts

About a week ago I noticed the digital clock located on my dashboard started losing individual lines of the numbers. For example an 8 would look like a 9 due to missing the lower left line of its display. Now, all numbers are missing lines and I even caught it running through the hours one right after another as if they were seconds.

Any thoughts? Does the clock run independently off its own battery or does it run off the battery in the vehicle?

Thanks in advance.

replace it