Pontiac GTO front and rear side marker bulbs utilize 168, 194, 194NA, 1157, and 1895 bulb sizes across different model generations. The replacement chart covers 1968 through 2006 production years with corresponding bulb size specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Pontiac GTO uses three T10 miniature wedge bulb types across its front and rear side marker positions: the 168, 194, and 194NA. All three share the same T10 form factor and operate at 12 volts, though their wattage ratings differ.
The 168 bulb is rated at 4.9W, while the 194 and 194NA are each rated at 3.78W. Despite sharing the same T10 base and housing shape, this wattage difference means the 168 draws more power than the 194 series under the same voltage.
The 194NA is a natural amber glass variant of the standard 194. Both share identical electrical ratings, with the amber tint built into the glass envelope rather than applied as a coating.
The front side marker positions on the 1969 and 1970 GTO specify the 194NA, indicating those model years required an amber light output from the bulb itself rather than from an amber lens.
The 1157 bulb, used in the rear side marker positions of the 2004-2006 GTO, is a dual-filament type with a BAY15d bayonet base. Its two filaments are rated at 21W and 5W respectively, which allows it to serve both a running light and a brighter signaling or braking function from a single bulb.
The BAY15d base of the 1157 is not interchangeable with the T10 wedge base used by the 168, 194, and 194NA bulbs. These two base types require different sockets and are physically incompatible with one another.
The 1969 GTO rear side marker uses the 1895 bulb, a T5 miniature wedge type rated at 0.9W. The 1968 rear side marker uses the 1893, also a T5 miniature wedge, rated at 2W. Both are T5 types but carry different wattage ratings and are not electrically identical.
The T5 bulbs used in the 1968 and 1969 rear side marker positions are physically smaller than the T10 bulbs used in other positions on the GTO. T5 and T10 wedge bases differ in width and are not interchangeable.
All bulb types listed across both sub-parts conform to ANSI standards applicable in both the United States and Canada, indicating standardized dimensional and electrical tolerances across all specified types.
The front side marker positions for the 2004-2006 GTO all specify the 168 bulb, while the 1970-1973 positions use 194-series bulbs. Although both are T10 wedge types, substituting one for the other would result in a wattage mismatch relative to the original specification.