CANBUS resistor 39 OHM 10W 12V - load resistor for LED | MAGALL

CANBUS resistor 39 OHM 10W 12V – load resistor for LED | MAGALL

A power resistor designed for 12V, used as an additional electrical load in LED lighting circuits.

Its job is to:

increase the current draw in the circuit,

lower the resistance seen by the system,

reduce bulb failure errors, flashing or ghost glowing of LEDs.

The resistor does not power the LED and does not light up – the electrical energy is converted into heat. This is the normal way a load resistor works.

Technical specifications:

Brand: MAGALL

Resistance: 39 Ω

Rated power: 10 W

Operating voltage: 12V

Type: load resistor CANBUS

Applications: 12V LED systems

Set: 2 pcs

Operating characteristics:

The 39Ω resistor creates a load of:

ok. 3.7 W at 12V

ok. 4.9 W at 13.8V

ok. 5.3 W at 14.4V

Important installation information:

⚠️ The resistor gets extremely hot – this is normal.

• mount only on a metal surface
• do not mount on plastic
• do not wrap in insulation
• ensure free air flow
• for left/right circuits use a separate resistor
• connect in parallel with the LED bulb, never in series

We debunk the 2 most common myths about CANBUS resistors

? Myth 1: “The resistor gets hot – it's a defect”

Fact: the resistor heating up is a normal and correct phenomenon.

The resistor creates electrical resistance and converts part of the electrical energy into heat – that is exactly why it is used in the circuit.

It is just as natural as:

• an iron heating up while in use,
• a kettle getting hot while boiling water.

That is why the resistor has an aluminium housing and must be mounted on a metal surface.

Heating up means the component is working correctly.

? Myth 2: “The more watts (W), the stronger the resistor works”

Fact: the watt (W) rating does not indicate current draw, but the maximum amount of heat the resistor can safely dissipate.

In simple terms:

• Ω (ohms) determine how the resistor works,
• W (watts) determine its safety and durability.

A higher-power resistor:

• does not change how the circuit works,
• does not increase current draw,
• provides lower operating temperature and longer lifespan.

✔️ Summary:

A CANBUS resistor is supposed to get hot, and the power rating (W) only tells you how safely it can do so.

CANBUS – how it works and why it matters for LED bulbs

CAN BUS (Controller Area Network Bus) is a car's internal communication network that lets electronic modules (e.g. the BCM – Body Control Module) exchange data without extra wiring.

The computer does not check whether the bulb actually lights up – it measures the current draw and the circuit resistance.

• Test when the ignition is switched on: the computer sends a short pulse and checks whether the resistance falls within the so-called acceptance window, i.e. the permitted range of values.
• Continuous measurement while driving: in more advanced cars the BCM constantly monitors the current. If the LED bulb has different characteristics from a halogen (e.g. lower current draw), the system may treat this as a fault and display a "bulb out" message.

In practice, different cars have different tolerance ranges and CANBUS standards – they differ in data transfer speed, how the circuit is tested, and resistance and power draw requirements.

So saying that an LED bulb "has CANBUS" or "doesn't have CANBUS" is a simplification. It all depends on the tolerance of the vehicle's diagnostic system and the parameters of the LED bulb itself.

An illustrative example of how it works:

an H7 halogen bulb has a resistance of 3,6Ω

1.

• an example H7 LED bulb has a resistance of 10 Ω
• car A (acceptable range) 2,5–7 Ω – warning
• car B (acceptable range) 2–12 Ω – no warning
• car C (acceptable range) 3–5 Ω – warning

2.

• an example H7 LED bulb has a resistance of 6 Ω
• car A (acceptable range) 2,5–7 Ω – no warning
• car B (acceptable range) 2–12 Ω – no warning
• car C (acceptable range) 3–5 Ω – warning

3.

• an example H7 LED bulb has a resistance of 2,5 Ω
• car A (acceptable range) 2,5–7 Ω – no warning
• car B (acceptable range) 2–12 Ω – no warning
• car C (acceptable range) 3–5 Ω – warning (short circuit)

Now you know why the same bulbs work without warnings for some users while for others the on-board computer reports a problem.

In our listings we state the technical parameters preciselyto make it easier to choose bulbs for a specific car model and avoid misunderstandings.