The Hummer H1 front and rear turn signal bulbs both utilize a 1157 size bulb for proper operation. The replacement chart covers 2002 through 2006 model 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 Hummer H1 uses the 1157 bulb for both its front and rear turn signals across the 2002-2004 and 2006 model years.
The 1157 is an ANSI-standardized bulb type, meaning its specifications are governed by a recognized North American standard applicable in both the United States and Canada.
The 1157 is a dual-filament bulb, meaning it contains two separate filaments within a single housing, allowing it to serve more than one lighting function simultaneously.
The bulb operates on a 12-volt electrical system, which is consistent with the standard automotive electrical architecture found in passenger and light-duty vehicles.
The two filaments in the 1157 are rated at 21 watts and 5 watts respectively, with the higher-wattage filament typically associated with the active turn signal function and the lower-wattage filament associated with a secondary function such as parking or running light duty.
The 1157 uses a BAY15d bayonet base, a two-pin offset base design that physically prevents incorrect installation by ensuring the bulb can only be seated in one orientation.
The shared bulb type across both the front and rear turn signal positions on the Hummer H1 means a single replacement part covers both locations on the vehicle.