| Light Type | Bulb Type |
|---|---|
| Low-beam headlights (2 bulbs) | H11 |
| High-beam headlights (2 bulbs) | 9005 (HB3) |
| Front signal/marker lamps | 3157/4157 LED family — four bulbs (two pairs) |
Low-beam replacement: H11
Start with the Alpha ReadyFit kit shown above. BTS has tested it on all 2008–2024 Peterbilt 389 model years with original factory halogen headlights. One kit includes two H11 low-beam bulbs, two 9005 high-beam bulbs and a pair of extended low-beam dust covers. For a standalone H11 replacement, compare the exact product’s application and installation requirements.
LED Bulb Replacement
Most LED low-beam installations on the Peterbilt 389 require BTS extended dust covers. A pair is included in the Alpha ReadyFit kit; consider the separate covers below for a compatible standalone-bulb installation. Check the fitted headlight and cap before ordering. LED headlight conversion bulbs may not comply with FMVSS/CMVSS requirements for on-road use. Check applicable state and provincial laws before use.
High Beam Replacement
The original factory halogen high beam uses 9005 (HB3). The Alpha ReadyFit kit includes two 9005 bulbs for this position. For another replacement, check the installed housing and the selected product’s mounting and cover requirements.
Compare compatible 9005 bulbs by their documented specifications and installation requirements. A shared bulb code alone does not establish fit in every replacement headlight assembly.
Signal Light Bulb Replacement
BTS-tested fitment: the Peterbilt 389 uses four 3157/4157 bulbs for its signal/parking/marker group. Choose amber replacements and order two pairs.
BTS-tested quantity: four signal/parking/marker bulbs — order two pairs. The Alpha and Morimoto amber options below are each sold as a pair. These four signal bulbs are separate from the four headlight bulbs and included dust covers in the base Alpha headlight kit.
BTS recommendation: choose Alpha for bright, reliable signal operation when the high-power signal circuit is not held on as a daytime running light. Alpha signal bulbs do not reduce their high-power output during sustained operation; do not use them for a continuously energized high-power signal DRL.
Morimoto XB alternative: supports standard and CK sockets. BTS has tested its protective output reduction during sustained signal-DRL operation on the T880 and W990. Morimoto separately excludes PWM-driven DRL circuits; contact BTS if that is your setup.
Follow the instructions for the exact LED product and check its operation on the truck. A CAN-bus label alone does not guarantee that every bulb warning or flash-rate issue will be resolved.
For the Alpha ReadyFit kit, use its engine-running warning check: turn on low beam, then high beam, and wait approximately one minute.
If a high-beam warning remains or returns when high beams are activated, follow the Alpha 389 installation guide for the supplied modules and retest. Choose that step from the warning check, not an assumed model-year programming cutoff.
The Alpha PWM modules below are a separate, connector-specific accessory for compatible 9–16V circuits. The ReadyFit kit already includes compact 9005 high-beam modules for its documented warning check. If a problem remains, check the bulb, power and connections, then contact BTS with the installed lamp and product details.
Peterbilt 389 headlight assemblies
For a complete headlight upgrade, compare the exact assembly’s listed years, factory equipment, side and wiring requirements. A replacement assembly can use different bulb sizes.
Shop NowFor a 2008–2024 Peterbilt 389 with original factory halogen headlights, use H11 for low beam and 9005 for high beam. Check replacement headlight assemblies separately.
One Alpha ReadyFit kit covers both beams with two H11 bulbs, two 9005 bulbs and a pair of extended low-beam dust covers. Most standalone LED low-beam installations need extended covers; check the selected bulb and fitted housing.
For the factory signal/parking/marker group, BTS confirms four 3157/4157 bulbs: two pairs. Keep replacement or modified lamp specifications separate.
Use the Alpha kit’s documented high-beam warning check to decide whether its included modules are needed. For other products, follow their own electrical and installation instructions.
Separate PWM modules have connector and circuit requirements. They do not replace diagnosis of a damaged connection, an incorrect bulb or another fault.
For complete headlights, use the assembly’s own application and installation details. Compare products by documented specifications and the equipment actually fitted to your truck.