Replacing the headlight bulbs on your Isuzu Trooper requires accessing the headlamp assembly in the engine compartment. It is a very simple process that requires only a clean rag and replacement bulbs. The Isuzu Trooper uses 9004-type bulbs for both the high beams and low beams; they can be purchased at most auto parts stores. The bulb replacement procedure should take you about 15 minutes.
Turn off the Isuzu engine and open the hood.
Disconnect the battery ground cable from the battery with a socket wrench.
Pull out the electric connector from the rear of the headlamp assembly.
Remove the rubber cap by turning it counterclockwise and pulling it off of the assembly.
Pull the bulb out of the assembly. With a clean rag wrapped around the bulb, install it into the assembly.
Reattach the rubber cap by rotating it clockwise. Reconnect the electric connector.
Reconnect the battery and close the hood.
