True CANBUS error free LED red brake lights.

[ecks]

Yep^^^ the LED is showing less resistance to the electrical management unit, that's why the check light is coming on, thinks something is blown.

I would also imagine that the load resistor would be dissipating a fair bit of heat, so it would require some form of heatsinking.

NO NO NO, it's showing MORE resistance, therefore LESS current is flowing!

[nomadx38]

I think you may be misinformed, though it sounds like you know a bit about electronics. Feel free to look this up on Wikipedia yourself but here is two parts of interest from "Electrical resistance and conductance":

"Geometry is important because it is more difficult to push water through a long, narrow pipe than a wide, short pipe. In the same way, a long, thin copper wire has higher resistance (lower conductance) than a short, thick copper wire."

"Objects such as wires that are designed to have low resistance so that they transfer current with the least loss of electrical energy are called conductors. Objects that are designed to have a specific resistance so that they can dissipate electrical energy or otherwise modify how a circuit behaves are called resistors."

A LOAD resistor would be placed in Series (not parallel as this would make two circuits side by side, thus the word "parallel") in the circuit to dissipate electrical energy (as heat) as to put more load on a circuit...

[wai]

Yep^^^ the LED is showing less resistance to the electrical management unit, that's why the check light is coming on, thinks something is blown.

I would also imagine that the load resistor would be dissipating a fair bit of heat, so it would require some form of heatsinking.

And that is the pity of the system. Instead of utilising the lower power draw of LED systems and being able to alter the triggering current of the alert, the "kludge" fix is to introduce a load resistor so that the system still believes that there is a normal light bulb there, and this sees no benefit in lower power consumption.

Many years ago I used relays to trigger a brake light fail on my Mini (back in 197. I used the current flow in the earth tail of the brake light, and this held relay contacts open. If the bulb failed, the current in the earth tail would be lost and the relay would close, triggering a light on the dashboard (or what passed for one on the Mini). With LEDs and modern electronics, the same thing could be done more simply.

[ecks]

I think you may be misinformed, though it sounds like you know a bit about electronics. Feel free to look this up on Wikipedia yourself but here is two parts of interest from "Electrical resistance and conductance":

"Geometry is important because it is more difficult to push water through a long, narrow pipe than a wide, short pipe. In the same way, a long, thin copper wire has higher resistance (lower conductance) than a short, thick copper wire."

"Objects such as wires that are designed to have low resistance so that they transfer current with the least loss of electrical energy are called conductors. Objects that are designed to have a specific resistance so that they can dissipate electrical energy or otherwise modify how a circuit behaves are called resistors."

A LOAD resistor would be placed in Series (not parallel as this would make two circuits side by side, thus the word "parallel") in the circuit to dissipate electrical energy (as heat) as to put more load on a circuit...

And if you place a conductor (Copper wire, zero ohms) across the terminals of a battery, very briefly (until a part of the wire becomes vapour) you will have a high wattage (low resistance) power drain (and probably an elementary light globe haha).

In the case of the 'load resistors" that are sold to correct globe errors, these are wired in parallel (one side to positive, one side to negative) to the light globe, and you should know that resistors in parallel decrease resistance, resistors in series increase resistance.

There will also be resistors in series with the "LED globe" on a PCB somewhere, but these are of no concern in the case, as the LED's are usually optimal on around 3 - 5volts.

Less resistance = Higher load. They're inversely proportional. Think about it some more.

[ecks]

No less resistance in this situation. the electrical system is looking for a load of .41amps (5 watts divide by 12 volts = .41Amp for a w5w Parker). When the system sees it it using less power than this (+ or - 10% or so) it displays the circuit as been open. A 1watt led is only pulling .08 amps as is counted as blown.

You aren't mixing up Watts (power) and Ohms (load), are you?

[nomadx38]

You know what you win. I'll just stick to what I know and it's working so far for the headlights, taillights, interior lights, neons and any electrical integrated circuit I have made for my car, home or computer so we will leave it at that.

[ecks]

You know what you win. I'll just stick to what I know and it's working so far for the headlights, taillights, interior lights, neons and any electrical integrated circuit I have made for my car, home or computer so we will leave it at that.

Hahaha I wasn't trying to be a prick or anything - I think semantics is what got in the way

[fastlane]

Where is the popcorn

I'm probs just gonna resistor it in the end as brake lights come out pink with these standard bulbs. I'm running CREE's and they are brighter and red! Hate how it pulsates due to error checking...

[nomadx38]

Hey Fastlane as I said to GTI JOE next get together I'm going to bring my VCDS cable so people can change their settings from steering feel to disabling diagnostics on light bulbs.

[fastlane]

Yeah thanks again mate! I will have to follow you up on that offer!

Just going to add resistors also, as I hate the glowing effect the system does to check for bulb outs!!!