Where is the starter solenoid on a 92 mercury?

WHat model Merc is it? Most are on the starter itself. Look at the starter, if it has a large wire and one or two small wires the sel is on the starter, if the starter has only one large wire and nothing else the sel is somewhere else, follow the large wire and you will find it.

-- Model would be helpful to determine this for sure. But here is the best way to find it on most cars. Find the positive battery terminal (+) on the battery. Follow the thick cable coming off that. It will either go to something bolted to the fenderwell (which should have some smaller wires & one other thick wire attached to it), or all the way down to a smaller cylinder mounted o nthe larger cylinder of the starter.

Either of those is the solenoid. Ford/Lincoln/Mercury often used the fenderwell mounted solenoids on their cars.

Another option for helping find parts is to go to the auto parts store (or their website, and look up the part, then look at what the new one looks like, and try to match that to something under the hood.