Chevrolet Astro Seat Belt Warning Bulb Size

The Chevrolet Astro seat belt warning light utilizes bulb sizes 194, PC74, and PC194 depending on the specific configuration of the instrument cluster. Data for the lighting components spans from 1985 through 1995.

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	PC194
1993-1994	PC194 (With Digital Inst. Cluster)
1993-1994	PC74 (Without Digital Inst. Cluster)
1985-1992	194

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Miniature wedge bulb (T10) with printed circuit board twist-lock socket, for instrument clusters. 12V, 3.78W.	PC194
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

Other Locations

Additional Notes

The PC194 and 194 bulbs share the same T10 wedge form and identical electrical ratings of 12V and 3.78W, yet they are not interchangeable. The PC194 uses a printed circuit board twist-lock socket designed for instrument cluster applications, while the 194 uses a standard wedge socket without that locking mechanism.
The PC74 is a T5 miniature wedge bulb rated at 12V and 1.4W, making it significantly lower in wattage than both the PC194 and the 194. Its printed circuit board twist-lock socket is shared with the PC194 in design type, but the two bulbs differ in physical size and power draw and are not substitutes for one another.
All three bulb types in these specifications conform to ANSI standards applicable in both the United States and Canada.
For the Chevrolet Astro, the seat belt warning bulb for model years 1985-1992 is uniformly the 194 across all trims, with no instrument cluster variation noted for those years.
In the 1993 and 1994 model years, the Astro seat belt warning bulb specification splits based on instrument cluster type. Vehicles equipped with a digital instrument cluster require the PC194, while those without the digital cluster require the PC74.
The 1995 model year specifies only the PC194, with no cluster-dependent split, indicating a single bulb type applies regardless of trim configuration for that year.
The transition from the standard 194 in 1992 to the PC-prefixed variants in 1993 reflects the introduction of printed circuit board socket requirements in the instrument cluster, which demand a twist-lock retention method rather than a simple wedge fit.