For a 1988 Mercury Marquis remove bottom shroud from steering column (5 Philips head screws). There is a wire running from the ignition switch to the left side of the steering column; detach it from the coupler (This can be done without a tool). Turn key to ON position until the panel lights come on. There is a small pin near the bottom of the key lock; push it in and pull the ignition switch out (don't panic if the wire seems to be stuck; it will come out). To replace, turn new ignition switch to same position. Push pin on the ignition switch in while sliding it back into the steering column. Reconnect wire and then replace shroud.
Why ? Just replace it.
Be more specific in your question. You haven't asked anything yet.
The 1991 Mercury Sable ignition switch is held in place with a retaining ring. Loosen the retaining ring. Pull the ignition switch out. Remove the wiring harness from the rear of the ignition switch. Reverse the process to install the new ignition switch.
it is on the firewall and difficult but not impossible to get to and replace.
found this, might be the same, Merry Christmas, anyways! :) For a 1988 Mercury Marquis remove bottom shroud from steering column (5 Philips head screws). There is a wire running from the ignition switch to the left side of the steering column; detach it from the coupler (This can be done without a tool). Turn key to ON position until the panel lights come on. There is a small pin near the bottom of the key lock; push it in and pull the ignition switch out (don't panic if the wire seems to be stuck; it will come out). To replace, turn new ignition switch to same position. Push pin on the ignition switch in while sliding it back into the steering column. Reconnect wire and then replace shroud.
on a 1997 Mercury Grand Marquis kill switch be activated by a rear end collision
You do not need a key to replace the ignition switch.
The 1986 Mercury Marquis does not have a fuel cutoff switch. The fuel pump does have a fuse, of which could render it as nonworking.
how can you start a '89 mercury cougar with a broken ignition switch?
check your brake lights if they not worhing replace fuse or brake light switch
how to replace an ignition switch for 2005 chevy equinox