L.E.D bulbs?

paul_white

Active Member
Feb 25, 2013
103
0
Derbyshire
thinking of getting some led tail light and indicator bulbs but cant find much info, has anyone got them? and how good/ bad are they?
 
Dec 5, 2007
888
0
N W Leeds
You have to put a resistor in series to keep canbus happy. Even though mine were "white" MOT tester wasn't happy with them, said they were blue and changed them. Only charged £4 so didn't complain.
With resistor you will still have same load so the crappy contacts that arc and corrode still do that. My front indicator ffauylted yesterdaqy, sure enough one of the contacts had arc eroded through. Crap design/cheap materials.
 

CraigFrTsi

"Dude I almost had you"
May 23, 2013
1,534
0
Stapleford, Notts
My sidelights

Before
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After
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paul_white

Active Member
Feb 25, 2013
103
0
Derbyshire
So no one has managed it yet? Sounds like a challenge! Anyone know what canbus version it is in an 06 tdi altia? And anyone have details on what the bulbs are e.g wattage, voltage (I'm assuming there 21w, @ 12v )
 

paul_white

Active Member
Feb 25, 2013
103
0
Derbyshire
You have to put a resistor in series to keep canbus happy. Even though mine were "white" MOT tester wasn't happy with them, said they were blue and changed them. Only charged £4 so didn't complain.
With resistor you will still have same load so the crappy contacts that arc and corrode still do that. My front indicator ffauylted yesterdaqy, sure enough one of the contacts had arc eroded through. Crap design/cheap materials.

What resistor did u use? And where did u put it? Was it just the one?
 

Dai_O

Active Member
Jul 30, 2009
154
4
Cardiff
you would need a resistor per bulb.

LEDs have a much higher resistance than a bulb, so by putting a low value resistor across each LED the CANBUS still thinks there is a normal bulb in place and doesnt throw a bulb fault.

this is normal BULB diagram, excuse the poor effort

+ _____mmm_______ GND
resistance from +'ve to ground is a few ohms


LED

+ _______|>|________ GND
High resistance end to end


LED and RESISTOR

+ _______|>|________ GND
.....|____[===]____|
With a resistor strapped across the LED, resistance is dropped and CAN is happy

Resistors can get hot so be careful where u mount them
Also LED bulbs will only work if put in the right way, reversed polarity they will not work, resistors will be fine either way around


Hope that helps

Dai O
 
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paul_white

Active Member
Feb 25, 2013
103
0
Derbyshire
Yeah I have a rough idea how Led's and resistors work, iv got some 6ohm resistors in the draw from an old project, but I know of a mod for the insignia relating to Led's and the can bus system , worked out u only needed to put a resistor on one of the number plate lights then u could put normal Led bulbs all round without any faults .

Just trying to find some information on how the can bus system reads an error on the lighting system then I can go from there, just read ur post again..... Would u say it's the amps being sucked by the Led's that would cause a fault on the can bus ? I'm thinking of trying out some smd Led bulbs which should have resistors built into the pcb.
 
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Wimbledonian

Active Member
Aug 31, 2010
667
3
milling around
The standard Altea rear bulbs are single-filament 21W for the tail/brake (braking puts full 12V through, tail alone is about half that). The rear indicators are only 10W, which is why they're so damn faint. This is because a 21W bulb is too fat to go trough the hole. You might find an LED unit that is bright and slim enough to fit, though.

The standard bulbs in the back are white and rely on the lenses for colour. However, bear in mind that white LED's do not filter in the same way and the advice is always to use red LED's for tail/stop, yellow for turn signals etc., even though you already have the coloured lenses.

So, good luck on finding LED's that (1) physically fit, (2) are the correct colour and (3) play with the CANBUS.

People have had success, however, fitting very bright CREE LED's into the reversing and fog lamps.
 

Wimbledonian

Active Member
Aug 31, 2010
667
3
milling around
Well, it's true that you can't simply dim LED's by reducing the voltage. People who have put LED's into their interior bulbs report the gradual dim being no more.
 
Dec 5, 2007
888
0
N W Leeds
Your resistors will need to be 25W rated at least, with a built in heatsink. Ordinary resin body ones will simply burn out.
LEDs are available with built in loading, I've fitted them to the fog light and reversing light