Just made a new dashboard for my Fury and have changed all the warning lights to smaller neater LED's.
All of them work ok, (indicators, oil, high beam etc) except for the ignition (charge ?) light, which only goes dimmer but stops on when the engine is started.
If I change it back to the old standard bulb type, it goes off as it should when engine is started.
Anyone know why the LED does'nt function as the standard bulb does and how I can get the LED to work?

wire the bulb in as well as the led (hidden behind the dash) - its to do with load and restance and stuff.... lol

[Edited on 24/2/12 by loggyboy]

quote:

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Originally posted by Tommy P
Just made a new dashboard for my Fury and have changed all the warning lights to smaller neater LED's.
All of them work ok, (indicators, oil, high beam etc) except for the ignition (charge ?) light, which only goes dimmer but stops on when the engine is started.
If I change it back to the old standard bulb type, it goes off as it should when engine is started.
Anyone know why the LED does'nt function as the standard bulb does and how I can get the LED to work?

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The way I understand it is that the alternator has got to sense some resistance through the bulb to excite the alternator so it knows its charging, the led doesn't have enough resistance for the alt to know about it, so the tip about including the bulb in the circuit as well as the led will sort the problem out nicely.

Cheers

Rich

Cheers for the replys.

So wire up the original warning light and then the LED from that and as the original bulb goes out, so too will the LED. Sounds good, so I'll give it a try.

I think it might need to be wired in parallel so the bulb effectively short circuits the LED to stop it coming on all the time.

When not running the original bulb is fed with 12v and grounded through the alternator. When the alternator starts spinning it is excited by the small current running back from the bulb and helps get the alternator to working at low RPM. Once the alternator is working it puts 12v out of charge light light wire and thus the bulb now has the same potential (2x positives) so cannot work and this goes off

IIRC you can wire the bulb up behind the dash and run the LED in parallel with it (in the correct orientation)

or use a resistor in parallel to the led/resistor, istr 150ohms from somewhere.

[Edited on 24/2/12 by iank]

Well I tried the bulb in line, but the led still stays on which ever way round I connect the terminals.
So I'll have to see if I can find the correct resistor. Or a warning light with bulb to fit an 8mm hole.
Cheers

Have you wired it in parallel or series?

well being totally rubbish with electrics I'll describe how I did it.
one of the original wires goes to one of the bulb terminals, out of the other bulb terminal the wire goes to one of the led terminals. The othe original wire goes straight to the other led terminal. If that makes sense.

Is the diode the right way round?

This works
(Bat)+12v ----->|---///--- +12 V (alt)

so when running this is effective that
0v ----->|----///-- 0V so LED OFF

When ignition on buy engine running
+12 V ----->|---///--- 0V LED ON

[Edited on 2/303/12 by mad4x4]

Needs to be like this




(Where 1 bulb is the LED, ignore the switch)

Not like this (series)



[Edited on 2/3/12 by loggyboy]

Cheers for that, I'll have another go at it tomorrow

Tom has just been over and i sorted it for him in 2 minutes lol.

No doubt he will be on to say thanks for the help and information but he really is totally rubish at electrics

ps, im crap too and managed it lol.

[Edited on 2/3/12 by welderman]

Yea thanks all.

Welderman to the rescue.

But I do wish he would'nt wear his underpants on the outside!!!

Tommy, you have u2u

Cheers Adi just replied