Peterbilt 330 Map Light Bulb Size

The Peterbilt 330 map light requires a 912 bulb size for the interior lighting component. Data for the specific bulb requirement covers the range from 2011 to 2017.

The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.

Bulb Size by Year Range

Years	Bulb Size
2011-2017	912

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Wedge bulb (T15). Variant of 921. 12V, 12W.	912

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Additional Notes

The Peterbilt 330 uses the 912 bulb for the map light across the 2011-2017 model years.
The 912 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 912 bulb uses a wedge base, which is a baseless design where the glass envelope itself is pinched at the bottom to form a friction-fit connection within the socket, requiring no separate metal base.
The T15 designation refers to the tubular shape of the bulb, with the numeric portion indicating a width of 15 eighths of an inch across the envelope.
The 912 operates at 12 volts and 12 watts, placing it within the standard low-voltage electrical architecture common to commercial vehicles.
The 912 is a variant of the 921 bulb. These two types share the same wedge base and envelope shape but differ in wattage, which means physical fitment into the same socket is possible while electrical output is not identical.
Because the 912 and 921 are variants rather than direct equivalents, substituting one for the other in the Peterbilt 330 map light socket would alter the light output and power draw of the circuit.