Check the speed sensor.
its something ps. i dont know that peps
The gears in the speedometer are stripped. If the odometer is working then you have input.
most odometer will need be repair by expert who cal odometer or replace the total meter
If it is like my 94, there is no cable, it is electronic. Run1
It is quite possible in a 1996 Mercury Cougar, that when the dashboard instruments all quit at once, there is a fuse that has been blown. Most of the gauges in the dash run off the same fuse in most vehicles.
remove dash replace bulb(instrument cluster)
Blown fuse, defective blower motor resistor pack, defective blower motor, or loose or disconnected wiring.
If the speedometer continues to work - probably a broken gear etc. in speedometer head and probably will have to be replaced. If speedometer does not work -- probably a broken speedometer cable
Most likely it is the VSS. Vehicle Speed Sensor. Have it checked out at your local garage or buy a new one and do it yourself. Although a computer check would be preferable first to obtain any codes.
The gears inside the odometer broke due to heat and age. You can buy the gears and replace them yourself. Or you can take your car to a place were they work on odometers.
If the gages in a 2000 Mercury Cougar at not working, it is likely that a fuse is blown. While the chance is slim, there could also be a wiring harness malfunction.
Check for a blown fuse.