How do you change the front combination light bulbs Infiniti I30 1998?

This is a relatively easy process; you should be able to replace both headlights within 15 minutes. And by the way, it's always a good idea to replace both light bulbs even if only one is burned out. Lights have a finite lifespan, and it's likely that your other light bulb will go out soon. Start by buying 9004 halogen bulbs. locate the back of the healight assembly in the engine compartment. There is a beige back up ring holding the light bulb in the headlight assembly. Turn the back up ring approximatley 90 degrees (1/4 turn) to the right. Pull the ring back along the wire. Grasp the plug assembly, and and pull the bulb (with wires attached) out of the headlight assmembly. To unplug the bulb, gently squeezing the black plastic static lock, and pull the plug assembly away from the lightbulb. Reverse the procedure to reinstall.