Starter solenoid replacement requires disconnecting the battery, the wires connected and removing and replacing the solenoid. Starter solenoids are usually mounted in one of two locations, either inside of the engine compartment or on the starter. Where your starter is located dictates the method used to access it.
Park the car in a safe place, with a level surface, before proceeding with repairs. A starter solenoid located inside the engine compartment is generally mounted to the fender near the battery. Locate it by following the red power cable from the battery to its connection point on the solenoid. Disconnect the negative cable from the battery post. Mark the wires, to note their location, before removing them by using the appropriate size wrench or ratchet and socket.
Remove the bolts connecting the solenoid mount to release the old part. Mount the new solenoid, and reconnect the wire as you marked it. Reconnect the negative battery cable.
Starter mounted solenoids are located under the engine block. Depending on the vehicle height to access it you may have to jack the vehicle up and place it on jack stands. Battery and solenoid wiring disconnection procedures remain the same. When removing the mounting bolts, the starter mounted solenoid may have shims or brackets that release and need to be kept for re-installation.
Unscrew the solenoid from the starter and replace it. Remount the unit to the starter, and connect the wiring. Lower the vehicle, and reconnect the negative battery cable.