NB1 Bulb Replacement
Difficulty: 1/5
Time to install: 10 mins
Tools Required: None
1999-2000 (NB1) Miatas take bulb styles H4. Please make sure to wear some suitable eye protection, as the bulbs may shatter and are under pressure. If your previous bulbs were on, allow them to cool. When handling the bulbs, do not touch the actual glass bulb area, as it can lead to premature burnout. If you do, carefully clean the lens with rubbing alcohol.
Pictured is what the rear of the headlight assembly looks like. You'll first want to remove the power connector. It is locked in by a small push tab in the top middle. Just press down on this and pull.
Inspect the harness, this one looks fine. Some Miata owners have complained about the harnesses overheating and melting, particularly the middle connection. If that is the case, you can replace them. Search online for "H4 Wiring Harness". They are about $4-6 USD to replace.
Remove the large, rubber donut, just grab the rubber tabs and pull.
Unlatch the bulb from the assembly. The bulb is locked in by a small wire pin, similar to a safety-pin as it's locked into its perch. Find the end opposite the hinged area, and push in towards the headlamp, and unhook it from its locking perch.
Pull the bulb out. Carefully replace it with a new bulb, holding it by the base. Return the clip into its position, slide the rubber grommet back on, and re-attach the wiring harness.