LED Advice Please - 1 resistor per bulb or per cluster

[imz]

Hi,

I have been in touch with T8ups to get my front headlamps converted to xenon but will need to wait a while as I have to get to him from London but will get LEDs all round at the same time.

In the meantime I had a reverse bulb out over the weekend so took out some LED bulbs that I had sitting around of another car. Now the bulbs are the same fitting but I get errors on the dash for the reverse and brake LEDs.

My question is if I fit one resistor on each of the rear clusters will they overcome errors on one bulb in each cluster or all the bulbs in each cluster?

Thinking of using something like this:

Many thanks

 

[gary_a4_quattro]

Hi Imz,

This is my take, as best as I understand it - haven't fitted any on my B7, just on a previous car.

Yes, 1 resistor per bulb - installed in parallel with the lamp, not in series.

Those resistors (6ohm / 50W) will be fine for 21W bulb, so, 'main' indicator lamps, stop light etc, (they will present the same load to the flasher relay so flash rate should be unaffected) Mount them onto somewhere where the heat can disipate and won't melt any trim, plastics etc - they will get hot. , it may indeed be possible to use higher resistance -

Side light, number plate light are lower wattage bulbs. typically 5W, thus draw lower current, so you would need a higher resistance to prevent excessive current draw on the side light circuit. Ohms law suggests 24ohm resistor, I've seen mentioned the people use 30ohm / 25W for side lights.

I wouldn't be suprised if a higher value could be used, some other member may well have direct experience on this.

 

[dimitar.tuntov.5]

and be carefull as they became hot when working a lot of time ... i use to have one in my headlights and was welded for the plastic case