GMC General front and rear side marker bulbs both use a 194 bulb size across all configurations. The replacement chart covers 1984 to 1988 model years with corresponding bulb specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The 194 bulb is the sole bulb type present across all listed front and rear side marker positions in these GMC specifications.
The 194 is classified as a miniature wedge bulb, using the T10 form factor, which refers to a tubular glass envelope roughly 10mm wide with a wedge-style base that requires no separate socket pins.
The 194 operates at 12 volts with a power draw of 3.78 watts, placing it in the low-wattage range typical of marker and clearance lighting applications.
The 194 carries ANSI standardization recognized in both the United States and Canada, meaning its physical and electrical characteristics conform to a defined industry specification rather than a proprietary design.
The GMC Tiltmaster uses the 194 bulb for its front side marker positions across the 1984-1988 model years.
Rear side marker fitment in these specifications covers the 1985-1987 model years, also using the 194 bulb.
Because the T10 wedge base is a standardized form factor, multiple bulb brands and variants, including LED replacements, are commonly produced to fit the same socket, though electrical compatibility with the vehicle's circuit should be considered before substitution.
The front side marker data spans a five-year range from 1984 to 1988, while the rear side marker data covers a three-year range from 1985 to 1987, with both sub-parts sharing the same 194 specification throughout.