The Peterbilt 282 front turn signal bulb size measures P21W or 199, while the rear turn signal bulb size measures 198. The replacement chart covers vehicle production spanning 1974 to 1980 with corresponding bulb size specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The P21W bulb is the front turn signal specification for the Peterbilt 282 across model years 1974-1977 and 1979-1980. It follows the ECE standard used in Europe and worldwide markets, operates at 12V and 21W, and uses a single filament with a BA15s bayonet base.
The 1978 Peterbilt 282 front turn signal uses the 199 bulb rather than the P21W. The 199 follows the ANSI standard used in the US and Canada and is a variant of the 1156 bulb type.
Despite the difference in standards, the P21W and the 199 share the same BA15s bayonet base and identical electrical ratings of 12V and 21W. Both are single-filament bulbs intended for signalling applications.
Because the P21W and 199 share the same base type and wattage, physical fitment between the two may be possible in some housings, though one follows ECE certification and the other follows ANSI certification, which reflects different regional regulatory frameworks.
The rear turn signal specification for the Peterbilt 282 is the 198 bulb across all listed model years, 1974-1980, without variation.
The 198 bulb is a miniature wedge type in the T5 form factor, rated at 12V and 2W. This is substantially lower in wattage than the front turn signal bulbs, which operate at 21W.
The T5 wedge construction of the 198 bulb means it has no base pins or bayonet fittings. It is held in place by the socket walls alone, which is a different retention method from the BA15s bayonet base used by the front turn signal bulbs.
The front and rear turn signal circuits on the Peterbilt 282 use bulbs with significantly different power draws, 21W at the front versus 2W at the rear, which reflects a design distinction between high-visibility forward signalling and lower-intensity rear indicator functions.