Chevrolet Astro Turn Signal Indicator Bulb Size

Additional Notes

• The turn signal indicator bulb specifications for the Chevrolet Astro span the 1985-2001 model years, with three distinct bulb types used across that range: 194, PC194, and PC74.
• The 194 bulb is a T10 miniature wedge type rated at 12V and 3.78W under the ANSI standard applicable to the US and Canada. It was the specified bulb for the Astro from 1985-1992.
• The PC194 shares the same T10 form factor, voltage, and wattage as the 194 but uses a printed circuit board twist-lock socket rather than a standard wedge socket, making the two bulbs non-interchangeable despite their otherwise identical electrical ratings.
• The PC74 is a T5 miniature wedge bulb with a printed circuit board twist-lock socket, rated at 12V and 1.4W. Its lower wattage distinguishes it electrically from both the 194 and PC194.
• From 1996-2001, the PC74 is the sole specified turn signal indicator bulb, representing a consistent fitment across those model years.
• The 1993 and 1994 model years present a split fitment: vehicles equipped with a digital instrument cluster require the PC194, while those without that cluster use the PC74. These two bulbs are not interchangeable due to differing socket types and wattage.
• The printed circuit board twist-lock socket used by both PC-prefix bulbs is specific to instrument cluster applications and is mechanically distinct from the standard wedge socket used by the non-prefixed 194 bulb.
• The 1995 Astro specifies the PC194 for the turn signal indicator, placing it as a transitional year between the earlier 194 fitment and the later PC74 fitment used from 1996 onward.