How to Replace an Alternator in an Isuzu Trooperby Don Bowman
Alternators for the Isuzu Trooper are manufactured in different amperages, so the alternator should be checked for this when replacing. The most common reason to replace alternators on a Trooper is that the diodes go bad. The amperage will be posted somewhere on the alternator, usually on the main body. The battery must be disconnected when replacing an alternator. If the radio has a code to prevent theft, it should be so noted. This code will be needed when the battery is reconnected.
Disconnect the negative terminal on the battery with a wrench. Remove the air pump bolts and air pump to gain access to the alternator. Use a 3/8-inch drive ratchet and a socket to remove the air pump.
Loosen the lower adjuster bolt in the alternator. Swing the alternator toward the engine, then remove the belt. Remove the large diameter, 10-gauge wire on the back of the alternator, which is the battery wire. Use a wrench to remove the nut securing this wire. Pull the plastic electrical connector from the back of the alternator.
Remove the upper and lower bolts in the alternator, using the 3/8-inch drive socket. Remove the alternator. Install the new alternator and parts in reverse order of removal.