How do you fix a bouncing failed speedometer on a 1997 Kia Sephia?

Answer 1

The first thing you should keep in mind is that it's illegal to operate a vehicle with a inoperative speedometer on any public streets so be careful because if stopped for speeding the offier will give you a choice between calling your own tow or letting him impound it, to answer your question.. since I had a recent related experience I need to know is the speedometer going all the way to the max with little acceleration? If so, you probably just need a new signal cable that connects from the speedometer to the MPH output terminal on your transmission. If the needle constantly flaps back in forth like a bird's wing, it's much more serious. Unfortunately if this ever happens than the only thing that will fix it is a whole new unit that goes in your dash. If it's only a 97 any auto part store can order a replacement or sites like e-bay sell a new, identical, or suitable replacement unit. Keep in mind however that if for example you installed a 2001 guage unit you'd probably have a working speedometer again but due to the differences in electronic layout with later models other guages all of the sudden may not function, or your night LED display may run all of the time not just when you turn on your headlights. It's tricky but if you handle it properly it's fixable. Be sure and check the indicator fuses and if there was ever an alarm installation that went bad because those things can cause issues like you described.

Good Luck, Matt

try changing your vehicle speed sensor in the transmission.