The ignition switch on a 1989 Jeep sends an electronic signal to the starter solenoid when you place the key in the ignition cylinder and turn the key to the "On" position. If you have determined that the ignition switch is defective and no longer sending the signal to the solenoid, you will need to replace the defective ignition switch. While a bit involved, the job is one that you should be able to tackle, and you'll only need a few basic tools to complete it.
Remove the screws holding the lower plastic cover to the steering column, using a Phillips screwdriver. Pull the lower cover off the steering column, followed by the upper cover.
Remove the illumination wiring harness behind the ignition-key lock cylinder by pulling down on the harness.
Remove the three mounting screws behind the cylinder lock that secure the switch to the column, using a tamper-proof Torx driver.
Pull the ignition switch and the cylinder lock away from the steering column.
Pry up on the two locks tabs that secure the ignition switch wiring harness to the switch, using a flat-head screwdriver. Pull the harness out of the switch.
Insert the ignition key into the cylinder lock and turn it to the "Start" position.
Locate the cylinder lock pin on the side of the switch and press the pin in with a flat-head screwdriver. Pull the lock cylinder out of the switch about 1/2 an inch. Remove the key and pull the lock cylinder completely out of the switch.
Slide the lock cylinder into the new ignition switch. Place the key in the lock cylinder and turn it to the "On" position. Slide the lock cylinder in the rest of the way. Remove the key.
Press the ignition switch wiring harness onto the new switch and press down on the locks with your fingers.
Secure the ignition switch to the steering column, using the three screws and the tamper-proof Torx driver.
Push the illumination wiring harness back into the ignition switch.
Position the top cover on the steering column, followed by the bottom cover. Secure them to each other with the screws, using a Phillips screwdriver.
