Chevrolet Blazer Automatic Transmission Indicator Bulb Size

The Chevrolet Blazer automatic transmission indicator requires bulb sizes 161, 194, and PC74 depending on the specific application. Data for the components covers the range from 1993 to 1997.

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
1995-1997	PC74
1994	194
1993	161

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Miniature wedge bulb (T5) with printed circuit board twist-lock socket, for instrument clusters. 12V, 1.4W.	PC74
ANSI standard (US & Canada). Miniature wedge bulb (T10). 12V, 3.78W.	194
ANSI standard (US & Canada). Miniature wedge bulb (T10). 12V, 1W.	161

Other Locations

Additional Notes

The PC74 is the most frequently specified bulb across these years, covering the 1995-1997 Chevrolet Blazer automatic transmission indicator. It is an ANSI-standard miniature wedge bulb of the T5 form factor, rated at 12V and 1.4W, and uses a printed circuit board twist-lock socket designed for instrument cluster applications.
The 1994 model year uses the 194 bulb, a T10 miniature wedge type rated at 12V and 3.78W. At 3.78W, it draws notably more power than either the PC74 or the 161 used in adjacent years.
The 1993 model year uses the 161 bulb, also a T10 miniature wedge type but rated at only 1W, making it the lowest-wattage bulb across all five years covered in these specifications.
Although the 194 and 161 share the same T10 form factor and both meet ANSI standards, their wattage ratings differ significantly. This distinction is relevant to fitment, as substituting one for the other may affect illumination output within the instrument cluster.
The PC74 uses a twist-lock printed circuit board socket, which is a physically distinct mounting interface from the standard wedge base of the 194 and 161. This difference makes the PC74 non-interchangeable with the bulbs specified for the 1993 and 1994 model years.
All three bulb types in these specifications are ANSI-rated for both the United States and Canada, indicating standardized electrical and physical tolerances across those markets.