Explore the Bulb Size Chart Below by Scrolling Down
| • Kenworth T600 | • Kenworth T660 |
| • Kenworth T680 | • Kenworth T700 |
| • Kenworth T800 | • Kenworth T880 |
| • Kenworth W900 | • Kenworth W990 |
Note. Classic sealed-beam models need separate handling from newer pod, HID, LED, or rectangular assemblies.
Accuracy and completeness are very important to us and our followers. If you notice any incorrect or missing information, please let us know so we can update the guide promptly. Your feedback is greatly appreciated.
Depending on the year of the model, some fitments may differ from the ones listed, please verify your sockets before purchasing.
Kenworth T600: identify the installed headlight
Start with the lamp number and housing fitted to your T600. A sealed-beam headlight, a housing with a removable bulb, and a complete LED assembly need different replacements.
For matching 4 × 6-inch sealed-beam housings
If your installed lamps are marked H4656 for high/low and H4651 for high-only, compare the two Holley RetroBright formats below. Match the beam function, mounting bucket and wiring to the replacement headlight instructions. These listings are sold individually.
Complete aftermarket LED headlamps
United Pacific lists its 31154–31157 and 35823–35826 LED assemblies for matching fender-mounted dual 4 × 6-inch equipment on T600 trucks. The catalog gives no model-year range for that application. These assemblies use LED light sources; their turn and position functions require additional wiring.
For another removable-bulb housing, use that housing’s bulb number. Identify front signals, markers and rear lamps separately; the T600 name alone does not establish a 3157 socket.
Source: United Pacific headlamp catalog, printed pages 41–42, for the identified replacement assemblies.
Kenworth T660 bulb sizes by headlamp
The original-style reference and a replacement housing can call for different low-beam bulbs. Check the housing part number before ordering.
| Reference / equipment | Low or dual beam | High beam |
|---|---|---|
| 2008–2011 T660 — Philips application catalog | H11 | 9005 |
This catalog entry covers 2008–2011. For another year or a changed headlamp, use the installed bulb and housing specification. The catalog’s LED-upgrade symbol does not change the original bulb designation.
United Pacific replacement housings: 2008–2017 T660
| Identified assembly parts | Low beam | High beam / other lighting |
|---|---|---|
| 31158 / 31159 / 31160 / 31161 | H11 | HB3; replace the original flasher with the included LED flasher as instructed |
| 32779 / 32780 / 32781 / 32782 | H7 | HB3; LED turn, position bar and side marker |
| 35771 / 35772 / 35773 / 35774 | LED | LED high beam, turn, marker and position functions |
The H7 and H11 rows describe different replacement assemblies. They are not interchangeable low-beam specifications. Follow the identified assembly’s mounting and wiring instructions; a complete LED assembly does not use these removable headlight bulbs.
Compare bulbs for the matching housing
Compare Alpha, GTR Lighting and Morimoto options when the installed housing accepts the matching LED bulb. Match the connector, bulb holder and cooling clearance. Follow the selected product’s installation instructions and stated intended use.
LED headlight conversion bulbs may not comply with FMVSS/CMVSS requirements for on-road use. Check applicable state and provincial laws before use.
H11 low-beam options
9005 high-beam options
H7 low beam for the identified United Pacific housing
For the H7 bulb specification in United Pacific 32779 / 32780 / 32781 / 32782 housings, compare the Alpha H7 below. The H7 listing currently shows backorder with an unknown ETA.
For front or rear signals and markers, identify the actual lamp separately. An LED signal built into one of these headlight assemblies does not establish the original truck’s signal bulb size.
Sources: Philips 2022 catalog, printed page 383; United Pacific headlamp catalog, printed pages 29–30.
Kenworth T680 bulb sizes by lamp type
Identify the headlamp fitted to your T680. Halogen, HID and factory LED equipment use different light sources. Kenworth’s shared T680/T880/W990 manual lists the specifications below; each row applies only to the matching installed lamp. Its January 2026 revision does not establish a model-year range.
| Lamp / equipment | Original specification | Source note |
|---|---|---|
| Low beam halogen | H11-LL (SAE), H7 (ECE) | (Long life version not required) |
| Low beam LED | N/A | Non-serviceable |
| Low beam HID | D1-S | — |
| High beam halogen | HB3A – LL | (Long life version not required) |
| High beam LED | N/A | Non-serviceable |
| Daytime running lamp/position lamp/turn signal/halogen side marker lamp | 4157K (SAE), 3157K (ECE) | N/A |
| LED Side marker | N/A | LED |
| Rear tail lamp/turn signal | N/A | LED |
SAE and ECE identify the equipment specifications printed in the manual. The combined daytime-running, position, turn and halogen-marker row is one source entry; it does not give a separate bulb count for each function. The LED side-marker and rear rows do not supply a replaceable bulb code.
Older 2013–2015 T680 reference
Philips’ 2022 catalog lists H11 in the low/dual-beam column for 2013–2015 T680 halogen capsule headlamps. A separate T680 row lists 9005XS for the high beam. Keep the XS designation when identifying that bulb and its connector. For an older HID headlamp, use its own bulb marking or service specification.
Headlight and signal bulb shopping
PACCAR headlamp instruction: Kenworth prohibits LED replacement light sources in PACCAR headlamps and warns that an incorrect bulb can overheat because of the internal optics. A replacement housing designed for LED bulb conversions must be selected using that housing’s instructions.
For a replacement housing that specifically accepts an H11 or 9005 LED bulb, browse the matching Alpha Series options below. For a lamp marked HB3A – LL or 9005XS, match the original bulb’s base and connector when selecting a replacement.
LED headlight conversion bulbs may not comply with FMVSS/CMVSS requirements for on-road use. Check applicable state and provincial laws before use.
The removable 4157/3157 signal family has its own LED choices. Compare the amber Alpha and Morimoto options for the matching lamp and circuit. Do not use the Alpha bulb where the high-power signal circuit stays on continuously as a DRL; the Morimoto listing excludes PWM-driven DRL circuits. A continuously lit lamp alone does not establish PWM operation.
Sources: Kenworth T680/T880/W990 manual, section 25.7, pages 326–327; headlamp instructions, pages 301–302. Philips 2022 Automotive Lighting Catalog, printed 383, for the older halogen entries.
Kenworth T700: match the installed bulb
Use the number on the installed bulb and the headlamp’s instructions when choosing a T700 replacement. A replacement housing can use a different bulb from the original headlamp.
The H11 and 9005 options below are for a housing that specifically accepts that LED bulb size. Match the connector, bulb holder and cooling clearance before selecting the bulb. For an integrated LED headlamp, identify the assembly instead.
LED headlight conversion bulbs may not comply with FMVSS/CMVSS requirements for on-road use. Check applicable state and provincial laws before use.
H11 options for a matching low-beam housing
9005 options for a matching high-beam housing
Compare Alpha, GTR Lighting and Morimoto. Follow the selected product’s installation instructions and stated intended use.
Check front signals, markers and rear lamps separately. Do not assume a 3157 bulb from the T700 model name. If the bulb marking is unreadable, contact BTS with the headlamp part number or a photo of the removed bulb.
Kenworth T800 bulb sizes by headlamp configuration
The Philips catalog lists three different headlamp configurations for 2003–2004 T800 trucks. Match the installed equipment; one bulb chart does not cover all three.
| 2003–2004 equipment | Low or dual beam | High beam |
|---|---|---|
| Two rectangular headlamps | H6054 | Not separately listed |
| Four rectangular headlamps | H4656 | H4651 |
| Halogen capsule headlamps | 9004 | Not separately listed |
For another model year or a changed housing, use the installed lamp number and its service instructions. “Two” and “four” describe the source’s headlamp configurations; they are not a quantity recommendation for a retail bulb kit.
Compare the matching sealed-beam replacements
The Holley 5 × 7-inch high/low listing includes H6054 in its compatibility details. For the four-headlamp setup, compare the 4 × 6-inch high/low and high-only listings. Match the lamp marking, beam function, mounting and wiring; each listing is sold individually.
9004 capsule-headlamp option
For a confirmed 9004 housing that accepts this LED conversion, the Alpha 9004 kit below uses 9007 LED bulbs with 9004 conversion adapters. This is the kit’s construction; it does not change the original 9004 reference.
LED headlight conversion bulbs may not comply with FMVSS/CMVSS requirements for on-road use. Check applicable state and provincial laws before use.
United Pacific also lists complete LED assemblies 31154–31157 and 35823–35826 for matching fender-mounted dual 4 × 6-inch T800 equipment, without a stated year range. Those assemblies have their own LED light sources and additional turn/position wiring requirements. Identify separate signals, markers and rear lamps by their installed bulb or assembly.
Sources: Philips 2022 catalog, printed page 383; United Pacific headlamp catalog, printed pages 41–42, for the identified replacement assemblies.
Kenworth T880 Bulb Size Chart
Start with the lamp fitted to your truck. Kenworth’s shared T680/T880/W990 operator manual covers multiple models and optional equipment; the table below applies only where your installed lamp matches the listed specification. Its January 2026 revision does not establish a model-year range.
| Lamp / equipment | Manual designation | Notes |
|---|---|---|
| Low beam — halogen | H11-LL (SAE) H7 (ECE) |
Long-life version optional. |
| Low beam — LED | N/A | Non-serviceable; contact your dealer. |
| Low beam — HID | D1-S | Where fitted; trained technician service. |
| High beam — halogen | HB3A – LL | Long-life version optional. |
| High beam — LED | N/A | Non-serviceable; contact your dealer. |
| Daytime running / position / turn signal / halogen side marker | 4157K (SAE) 3157K (ECE) |
Match the installed lamp specification. |
| LED side marker | N/A | LED; no bulb code specified. |
| Rear tail / turn signal | N/A | LED; no bulb code specified. |
Shop Kenworth T880 9005 LED high beams
BTS-tested high-beam fit: the original Kenworth T880 halogen specification is HB3A-LL; shop 9005 LED high-beam replacements. BTS has confirmed that its current Alpha, Morimoto and GTR 9005 offerings fit the original high-beam housings without clearance issues. The original code is retained for reference; it does not require a separate LED shopping size.
Choose from Alpha, Morimoto 2Stroke 4.0 and GTR Ultra 3.0 below. The Morimoto and GTR listings each contain two bulbs. These high-beam products are separate from the signal bulbs.
Choose signal bulbs by your DRL setting
BTS-tested quantity: two 3157/4157 signal bulbs — one pair. The T880 and W990 use one pair for this signal/parking group. This is separate from the headlight bulbs.
- Low-beam DRL, or signal DRL disabled: BTS recommends Alpha amber bulbs for brightness and reliability.
- High-power signal circuit used as the DRL: BTS recommends Morimoto XB amber bulbs. In BTS testing, their output visibly reduces after the circuit stays energized, protecting the bulbs during sustained use.
Alpha signal bulbs do not step down in sustained high-power mode and can eventually fail in that DRL application. Kenworth dealers can change the T880/W990 DRL programming between the signal-light and low-beam settings. Choose by the truck’s actual programming.
Product note: Morimoto XB supports standard and CK sockets. Its separate exclusion for PWM-driven DRL circuits still applies; contact BTS if that is your setup.
These are original incandescent designations. For LED replacements, shop the 3157/4157 family and match the required light colour, socket wiring and DRL function. SAE and ECE identify the manual’s equipment specifications.
For fog, reverse, license-plate or roof-clearance lamps, check the installed lamp or ask your dealer; this chart supplies no bulb code for those positions.
PACCAR headlamp instruction: PACCAR prohibits LED replacement light sources in its headlamps. The manual warns that an incorrect bulb can overheat because of the internal optics and cause a fire. Follow the headlamp manufacturer’s instructions when selecting replacements.
Source: Kenworth T680/T880/W990 Operator’s Manual, Y53-1200-1N1 (January 2026), section 25.7, pages 326–327; headlamp service and replacement guidance, pages 301–302.
Read the full Kenworth T880 bulb guide for lamp identification, replacement-housing options and installation details.
Kenworth W900 sealed beams and replacement housings
Start with the lamp shape and the number on the installed headlight. Round and rectangular sealed beams have different high-only and high/low positions. A housing with a removable bulb uses that housing’s specification.
| Installed sealed-beam format | High/low lamp | High-only lamp |
|---|---|---|
| 5.75-inch round, four-lamp arrangement | H5006 — three terminals | H5001 — two terminals |
| 4 × 6-inch rectangular arrangement | H4656 | H4651 |
Holley’s installation chart identifies H5006 as a high/low lamp and H5001 as a high-only lamp. Read the existing lamp number rather than choosing by shape alone. Holley requires verification of the ground, low-beam and high-beam wiring; an adapter or connector change may be needed.
Holley RetroBright complete headlight kits
Compare the W900A 5.75-inch round kit and the W900B/W900L 4 × 6-inch rectangular kit below. Match the kit to the truck’s installed lamp format and choose the required colour option. These are complete replacement headlights.
United Pacific housings with replaceable 9007 bulbs
United Pacific 31388 and 31390 are specific 4 × 6-inch replacement modules supplied with a 9007 halogen bulb. Their manufacturer application list includes 1983–2020 W900 trucks. This is the application of those modules, not an original W900 bulb chart.
| Replacement module | Included connection / position |
|---|---|
| 31388 — high/low headlight | 9007-to-H4656 adapter 34206; the description identifies its low-beam location |
| 31390 — high-only headlight | 9007-to-H4651 adapter 34208; high-beam module only |
United Pacific warns that the original W900 headlight bucket may need modification. Each listing is for one module; choose the positions and quantity required for your installation.
For another aftermarket housing, front signal, marker or rear lamp, use the installed part’s bulb specification. The W900 name alone does not establish H11, 9005 or 3157 bulbs.
Sources: Holley RetroBright installation instructions 199R12350, page 2; United Pacific 31388 and 31390 specifications and W900 application lists.
Kenworth W990 Bulb Size Chart
Shop Kenworth W990 9005 LED high beams
BTS-tested high-beam fit: the original Kenworth W990 halogen specification is HB3A-LL; shop 9005 LED high-beam replacements. BTS has confirmed that its current Alpha, Morimoto and GTR 9005 offerings fit the original high-beam housings without clearance issues. The original code is retained for reference; it does not require a separate LED shopping size.
Choose from Alpha, Morimoto 2Stroke 4.0 and GTR Ultra 3.0 below. The Morimoto and GTR listings each contain two bulbs. These high-beam products are separate from the signal bulbs.
Choose signal bulbs by your DRL setting
BTS-tested quantity: two 3157/4157 signal bulbs — one pair. The T880 and W990 use one pair for this signal/parking group. This is separate from the headlight bulbs.
- Low-beam DRL, or signal DRL disabled: BTS recommends Alpha amber bulbs for brightness and reliability.
- High-power signal circuit used as the DRL: BTS recommends Morimoto XB amber bulbs. In BTS testing, their output visibly reduces after the circuit stays energized, protecting the bulbs during sustained use.
Alpha signal bulbs do not step down in sustained high-power mode and can eventually fail in that DRL application. Kenworth dealers can change the T880/W990 DRL programming between the signal-light and low-beam settings. Choose by the truck’s actual programming.
Product note: Morimoto XB supports standard and CK sockets. Its separate exclusion for PWM-driven DRL circuits still applies; contact BTS if that is your setup.
H11 anti-flicker support for matching installations
This H11 module is rated for 9–16V systems. Match the H11 connector and follow the module and lamp instructions. It is not a universal remedy for every Kenworth warning message, flicker problem or DRL circuit.
Due to manufacturer-specific variations, the information in the table may not be 100% accurate.
If you notice any incorrect information or have additional details to contribute, please feel free to contact us. We truly appreciate all customer feedback and input. support@btslighting.com
FAQs
Check the headlight housing and the original bulb. Halogen systems usually use replaceable bulbs such as H11, 9005, 9007, or sealed-beam lamps. HID systems use HID bulbs such as D1-S with a ballast. LED systems may use integrated modules or full headlight assemblies.
If the headlight has no removable bulb, it may be a factory LED or aftermarket LED assembly.
Many Kenworth halogen bulbs can be upgraded to LED replacement bulbs, but the LED must match the original bulb size and fit the headlight housing correctly.
Before installing LED bulbs in a Kenworth truck, check bulb size, heat sink clearance, dust cap space, connector fitment, beam pattern, and whether the truck needs anti-flicker support.
Not always. Some Kenworth headlights use separate low beam and high beam bulbs, while other setups use a dual-function bulb or sealed-beam lamp.
Some Kenworth LED headlights do not use standard replacement bulbs. Factory LED and aftermarket LED headlight assemblies may use integrated LEDs, service modules, or complete assembly replacement.
If your Kenworth has LED headlights, check the assembly service information before ordering halogen-style bulbs.
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