Kenworth W900B/W900L Lights

Frequently Asked Questions About Kenworth W900B/W900L Lights

What's the difference between W900B and W900L light fitments, and will they interchange?

The W900B (short hood) and W900L (long hood) models use different headlight buckets and mounting configurations. While many auxiliary lights like cab markers and turn signals are interchangeable between models, headlights and grille-mounted lights often require model-specific fitments. The W900L's extended hood requires longer wiring harnesses and different mounting brackets. Always verify your specific model year and hood type before ordering, as Kenworth made subtle changes throughout production years.

Are LED conversions worth it for my older W900, and what do I need for installation?

LED conversions typically provide 3-5 times longer lifespan than halogen bulbs and draw significantly less power, reducing strain on your electrical system. For a complete LED conversion, you'll need compatible housings (not all factory housings work with LED bulbs), proper load resistors for turn signals to prevent hyper-flashing, and potentially a relay upgrade for older trucks. Most LED headlights are plug-and-play with H4 connectors, but pre-1990 models may require connector adapters. Budget 2-4 hours for a full conversion including headlights, markers, and turn signals.

Why do my new aftermarket headlights have condensation issues, and how can I prevent this?

Condensation in aftermarket lights is often caused by inadequate sealing or missing breather vents. Quality lights should have proper drainage channels and breathable yet waterproof vents. Before installation, apply a thin bead of clear silicone around the lens seal (don't overdo it), ensure all factory drain holes are clear, and check that rubber boots on the back are properly seated. If condensation persists, drill a small 1/8" weep hole at the lowest point of the housing. Avoid cheaper lights without proper ventilation systems, as they're prone to chronic fogging.

What are the correct bulb sizes for all the lights on my W900B/W900L?

Standard bulb sizes for most model years include: Headlights - H4 (9003) for sealed beam conversions or 7" round sealed beams; Turn signals - 1157 (front) and 1156 (rear); Cab markers - 194 or 168; Side markers - 194; Fog lights - H3 or 9006 depending on housing; Interior dome - 1003 or 1141. Years 2007 and newer may use different configurations, particularly for LED-ready trucks. Always verify with your specific year's manual, as Kenworth occasionally changed specifications mid-year.

Can I install projection-style or HID headlights on my W900, and what problems should I expect?

Projection and HID conversions are possible but require careful consideration. The deep-set headlight buckets on W900s can cause beam pattern issues with some projector designs, creating dark spots or insufficient spread. HID systems need proper projector housings (never use HID bulbs in reflector housings) and may require additional relays and capacitors for reliable operation. Many drivers report better results with high-quality LED alternatives that provide similar brightness without the complexity. If pursuing HID, expect to spend $400-800 for a quality kit and allow 4-6 hours for proper installation including aim adjustment.