My speed meter went off after my drive shaft were replaced.

What could be the problem n how do i go about getting it fixed because i don't like driving with my speed meter idle. before i replaced my drive shaft, the speed meter was perfectly in good working condition but after the replacement, it refused to come back to life.

Went back to the auto-mechanic but he told me he didn't touch any wire to the gearbox. what can i do and how do i go about rectifying it back to normalcy because i dislike the idea of driving without the speed meter in good working condition.