Why won't a 1994 Mercury Trio start with the key but it will if you put power to the starter solonid ignition switch or neutral switch?

Answer 1

Just guessing here, but it sounds like you need a PATS key to start your car. (passive anti-theft system). I don't know if your particular vehicle requires one, look in the owner's manual. If you have the original Mercury key, it would have a plastic head containing a computer chip (transponder). Contact your local Ford, Mercury, Lincoln dealer and ask for the Parts Dept., or a help desk. Have your make, model and VIN number handy. If your car needs a pats key, dealer prices can be high, try getting one on ebay. You'll still need to go to a dealer or a specialized locksmith shop and have it programmed. If you find out that your car doesn't require a pats key, then I'd check to see if the ignition key tumbler needs replaced.