Chevrolet Blazer Seat Belt Warning Bulb Size

Additional Notes

• The seat belt warning bulb specifications for the Chevrolet Blazer span the 1987-2003 model years and reference five distinct bulb sizes: PC74, PC194, 74, 194, and 168.
• The PC74 and 74 bulbs share identical electrical ratings of 12V and 1.4W and both follow the T5 miniature wedge form factor. The PC74 variant adds a printed circuit board twist-lock socket, making it specific to instrument cluster printed circuit board applications.
• The PC194 and 194 bulbs similarly share the same 12V, 3.78W rating and T10 miniature wedge form factor. As with the PC74 and 74 pairing, the PC194 designation indicates a printed circuit board twist-lock socket, while the 194 uses a standard wedge base.
• The 168 bulb is also a T10 miniature wedge type rated at 12V but draws 4.9W, which is higher than the 194 and PC194 bulbs despite sharing the same form factor. This wattage difference makes the 168 non-interchangeable with the 194 or PC194 in applications where power draw is a factor.
• The Chevrolet Blazer used the PC74 for the seat belt warning indicator across the 2000-2003 model years, while the 1995-1999 model years used the higher-wattage PC194.
• The PC-prefixed bulb types (PC74 and PC194) are designed specifically for printed circuit board sockets. Substituting a standard wedge base bulb such as the 74 or 194 in a printed circuit board socket position is not supported by these specifications.
• The 168 bulb was specified for the 1987-1988 model years, representing the only use of that bulb size across the entire listed range for this application on the Blazer.
• All five bulb sizes listed conform to ANSI standards applicable in both the United States and Canada, and all operate on a 12-volt electrical system.