Mercury Repair Questions? Ask a Mechanic for Answers ASAP
When you say everything stopped working did it seem like the dash was just going blank?
The engine ran ok until you turned it off?
I would be more suspect of a bad instrument cluster assembly. The instrument clusters on these cars go bad all of the time and the starting circuit depends on the cluster in order to allow the vehicle t start.
Will the engine crank at all?
When you turn the key to the on position does anything come on?
Gauges, headlights, radio, etc?
Is it possible that the battery is dead? I'm wondering if maybe the alternator went out and the battery died. That will sometimes cause the instrument panel to stop working while driving because it needs a constant voltage in order to operate correctly.
I think your battery is dead or dying. My first suggestion would be to have it tested.
If you can get it to jump start, and then the car does out or the electronics start acting up once the jumper cables are removed then you most likely have an alternator problem. Both the alternator and battery can be tested fairly easily by most parts stores.
A loose battery cable would cause the alternator to not charge correctly and would also cause a bad ground to just about everything that relies on a chassis ground to operate correctly. If it was loose enough I would say that is probably the problem.