Probably a bad starter solenoid.
It could be the battery. If not try tapping the starter with a hammer. Not hard enough to crack the housing but hard enough that it might unstick the starter from the flywheel. If this works you might want to change the starter. If not it would have to be the solenoid.
Most commonly, it's the starter or the starter was wired wrong when it was installed. More rarely, it can also be the keyswitch or even a bad gear on the flex-plate.
The Amperage draw is so high it locks the starter solenoid. This can be because of a bad starter bushing, low voltage in the battery, timing, etc. It is a major engineering defect in the design. All Fords prior to 1992 have this flaw. It can result in a fire, dead battery, etc. The good news is Ford redesigned their starters in 1992. The new starters will fit the old engines and Ford sells a retrofit kit to rewire the Solenoid for the new starter. The way it corrects the problem is the old solenoid becomes a starter relay, with the output wire now going to a solenoid mounted on the new starter. (This gives you less of a voltage drop at the new solenoid vs the old solenoid, that solves the problem in most cases) You need to buy the kit from Ford (Under $20.00) but you can buy the starter anywhere. Just give them your vehicle information as if you owned a 1993 Ford when buying the starter. You can also get a rebuilt starter from Ford. You could make your own kit, but the Ford Kit is everything you need and comes with instructions (priceless). Warprunner
If it is a automatic transmission there is no starter relay but, an ignition relay instead. If it is manual the starter relay is located under the hood at the fuse box on the left (drivers) side.
on the starter its self>>>>JAC
The solenoid is located on the passenger side on top of the starter motor.
The starter solenoid is on the left side fenderwell next to the battery.
may be on top of the starter and replaced with same. Follow the + battery cable it will connect to the solenoid
On the starter.
On the 1993 Cadillac 4.9L the soleniod is located atop the starter.The starter is afixed directlyto the side of the motor at the front of the car behind the radiator.
The starter and solenoid are mounted together on the bottom front side of the engine
Starter Solenoid? Located on top of starter Disconnect electrical connection between starter and solenoid--1/4 or 5/16 bolt on bottom of solenoid Remove 2 screws and twist--spring loaded
The starter solenoid is mounted directly to the starter. Just follow the positive battery cable from the battery, it will lead you right to the starter solenoid.
The starter solenoid is the small (about 1 or 2 inch diameter) cylinder attached to the much larger cylinder that is the starter itself. This is usually located on the drivers side of the engine, low down and to the rear, attached to the transmission bellhousing. The positive battery cable will lead you straight to it, and attaches to the solenoid.
It's located on the side of the starter.
On the starter.