Overview
When upgrading to LEDs or HIDs, many modern vehicles trigger warning lights or cause the new bulbs to flicker. These issues occur because the vehicle’s CAN‑Bus system expects the higher current draw of a halogen bulb or because the daytime running light circuit uses PWM pulses. Our compact 9005 Canbus PWM decoder is designed specifically for vehicles with limited space — like the Peterbilt 389, 567 and 589 headlight buckets — where full‑size decoders do not fit but proper load simulation is still required.
How it works
This inline harness plugs between your vehicle’s factory connector and your new LED or HID bulb. Inside the slim housing is a load‑resistor and capacitor circuit similar to full‑size decoders. The resistor adds electrical load so that the vehicle’s body control module senses a halogen‑like current and stops issuing a bulb‑out warning. The capacitor stores energy and smooths PWM pulses, eliminating flicker and dimming when DRL circuits use pulsed voltage. Together, these components provide a stable supply to your LED bulb and ensure error‑free operation.
Features & benefits
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Compact form factor: At roughly half the size of our full‑size 9005 PWM module, this decoder fits inside the smallest headlamp housings without drilling or modifying dust covers. It is ideal for Peterbilt 389/567/589 trucks as well as cars and SUVs with tight space behind the headlight.
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Wide compatibility: Supports 9005 (HB3), 9006 (HB4) and 9012 (HIR2) bulb bases (and compatible variants like 9005A/H10/9145). Works with LED headlights, fog lights or DRLs. Not recommended for HID ballasts that exceed 4 A draw.
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Stable power & reduced noise: The upgraded resistor‑capacitor design eliminates flicker, solves radio‑frequency interference, and prevents the lights from shutting off when the engine starts. The aluminum heat‑sink housing provides adequate dissipation despite the smaller size.
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Quality construction: Weather‑sealed connectors with silicone gaskets ensure durability in harsh environments. The module is rated IP65 and can be mounted using the included double‑sided tape or zip ties.
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Plug‑and‑play: Clearly marked positive (+) and negative (–) leads simplify installation. Simply disconnect your factory plug, insert the decoder in‑line, and reconnect your bulb. No cutting or splicing required.
Fitment and compatibility
This compact decoder is suitable for most vehicles using 9005, 9006, 9012 or 9145/H10 bulb bases, including heavy‑duty trucks, passenger cars and motorcycles. It is particularly helpful for vehicles that:
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Use a CAN‑Bus electrical system and display bulb‑out warnings when LED bulbs are installed.
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Use pulse‑width‑modulation (PWM) DRLs, causing LEDs to flicker or dim.
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Have tight headlamp housings where full‑size decoders cannot fit, such as Peterbilt 389, 567 & 589 trucks.
If your vehicle does not have a CAN‑Bus system or you are not experiencing bulb‑out errors, a decoder may not be necessary. For vehicles drawing more than 4 A per bulb or requiring a higher load, our full‑size 9005 PWM module may be more appropriate.
Installation tips
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Disconnect the battery and remove the headlamp or access panel.
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Unplug the factory 9005/9006/9012 connector and plug it into the input side of the decoder.
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Connect the output side of the decoder to your LED or HID bulb. Ensure the positive and negative terminals match.
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Secure the decoder inside the headlamp housing using the included tape or zip tie. Avoid placing it near plastic or wiring that could melt from heat.
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Reinstall the headlamp, reconnect the battery and test the lights. If flickering persists, reverse the polarity or ensure all connections are tight.
FAQs (Schema‑ready Q&A)
Q: Will this compact decoder fix bulb‑out warnings on my Peterbilt 389, 567 or 589?
A: Yes. The resistor inside the decoder simulates the load of a halogen bulb, which stops the body control module from triggering a warning. Our compact design is sized for the tight headlamp bucket used on these trucks, making it an ideal solution.
Q: Can I use this module with 9006 or 9012 bulbs?
A: Absolutely. The connector and wiring support 9005 (HB3), 9006 (HB4) and 9012 (HIR2) bulbs as well as H10/9145 variants. Always ensure the current draw stays within the decoder’s 4 A per module rating.
Q: Does it work with HID kits?
A: Yes, but only for low‑wattage HID kits drawing up to 4 A. Higher wattage ballasts may require a larger decoder or relay harness.
Q: My LEDs flicker only in daytime running light mode. Will this fix that?
A: Vehicles using PWM for DRLs send power in pulses. The decoder’s capacitor converts the pulsed supply into a steady voltage, preventing flicker.
Q: What if my vehicle still displays an error or flickers?
A: Some vehicles have unique electrical systems and may require a more powerful load resistor or a dedicated relay harness. If errors persist, please contact our support team for troubleshooting.
Q: Do I need a decoder if my vehicle isn’t CAN‑Bus equipped?
A: No. Decoders are designed to work with CAN‑Bus systems. If your vehicle lacks a CAN‑Bus system and you do not experience flickering or warnings, the decoder isn’t necessary.
Warranty and support
Each decoder pair is covered by a 1‑year warranty against manufacturing defects. BTS Lighting stands behind our products with Canadian technical support and fast shipping from our Saskatoon warehouse.
Conclusion
A CAN‑Bus decoder harness is essential for error‑free LED or HID upgrades in modern vehicles. By simulating the load of a halogen bulb and smoothing PWM signals, decoders stop flickering, prevent bulb‑out warnings and improve compatibility. The BTS Lighting compact 9005/9006/9012 PWM decoder takes these benefits and packages them in a space‑saving design ideal for tight headlamp housings like those on Peterbilt 389/567/589. With plug‑and‑play installation, multi‑bulb compatibility and robust build quality, it provides a simple solution to one of the most common challenges when upgrading to high‑performance LED lighting.
