The GMC PM253 high beam and low beam headlight bulbs both utilize the H6006 bulb size. The replacement chart covers vehicle production spanning 1952 to 1955.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The GMC PM253 uses the H6006 bulb size across both the high beam and low beam headlight positions for the 1952-1955 model years.
The H6006 is an ANSI-standardized sealed beam unit recognized in both the United States and Canada, operating at 12 volts.
A sealed beam unit integrates the filament, reflector, and lens into a single fused glass assembly, meaning the entire unit is replaced rather than an internal bulb.
The H6006 follows a 5x7-inch rectangular form factor, which is a standardized size shared across many vehicle applications of that era, making cross-brand fitment possible where the same specification is listed.
Because the H6006 serves both the high beam and low beam positions on the GMC PM253, a single sealed beam type covers the full headlight system on this vehicle.