GMC C3500HD Map Light Bulb Size

The GMC C3500HD map light utilizes bulb sizes 168, 561, and 211-2 depending on the specific version of the vehicle. Available information covers the period from 1993 through 2002.

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
1999-2002	168
1998	561
1997	168
1995-1996	211-2
1994	168
1993	211-2

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Miniature wedge bulb (T10). 12V, 4.9W.	168
ANSI standard (US & Canada). Festoon bulb, 44mm length, end-cap contacts. 12V, 12W.	561
ANSI standard (US & Canada). Festoon bulb, 41mm length, SV8.5 base. 12V, 12W.	211-2

Other Locations

Additional Notes

The GMC C3500HD map light bulb specifications cover model years 1993 through 2002, with three distinct bulb types used across that span: the 168, the 561, and the 211-2.
The 168 bulb is the most frequently specified type across these years, appearing in 1994, and 1997 through 2002. It is a T10 miniature wedge bulb rated at 12V and 4.9W, conforming to ANSI standards for the US and Canadian markets.
The wedge base of the 168 bulb means it is held in its socket by friction rather than by a separate locking mechanism, which is a defining characteristic of the T10 form factor.
The 211-2 festoon bulb is specified for the GMC C3500HD in 1993, 1995, and 1996. It measures 41mm in length, uses an SV8.5 base, and is rated at 12V and 12W, also under ANSI standards.
The 561 festoon bulb is specified solely for the 1998 model year. Like the 211-2, it operates at 12V and 12W, but it uses end-cap contacts rather than an SV8.5 base and measures 44mm in length.
Although the 211-2 and 561 share identical voltage and wattage ratings, their physical configurations differ. The 3mm difference in length and the distinct contact types make them non-interchangeable without modification to the socket.
The 168 wedge bulb at 4.9W draws considerably less power than either festoon type at 12W, reflecting a fundamental difference in bulb construction and intended application rather than a variation in vehicle electrical systems.
Festoon bulbs, such as the 211-2 and 561, are cylindrical in form and make contact at both ends of the bulb body, a design commonly associated with interior dome and map lighting applications.
The 1997 and 1999-2002 model years share the 168 bulb specification, while the surrounding years of 1996 and 1998 each call for a different festoon type, indicating that socket design changed at least twice within this production run.
All three bulb types listed carry ANSI designations valid for both the United States and Canada, meaning the part numbers are standardized across those two markets.