just got the car like 3 weeks ago off my friend and my next project is fixing the speedometer. He said it stopped working after the auto start and alarm was installed. The mileage on the odometer doesn't work either. Just looking for trouble shooting tips. I think it could be a speed sensor problem but there's a good possibility that it is a wiring issue

 

they could have cut a wire, its going to be a nightmare to figure it out. Good luck.