Ign Warning Light Puzzle
jonti - 15/3/04 at 04:42 PM
This has me foxed at the moment but I'm sure one of you wizzkids can explain.
As a temporary set-up I had a 25w flasher bulb wired to the sense tag on my Diahatsu alternator to act as an Ign Warning Light. It worked fine.
On Saturday at Stafford I purchased a pukker set of lamps with little symbols on 'em from Europa. they have 4w bulbs in 'em.
Sequence of events when I got home was then as follows:-
Wired new Warning Lamp in place of Winker Bulb in Ign Warning circuit.
Didnt work......thinks... duff bulb maybe?
Insert new bulb..still didnt work.
Tried new bulbs across battery......bulbs ok
Reconnect winker Bulb to ign warning circuit....works ok
Scratch head
By pure fluke discovered that if both Winker bulb and New Warning Light are wired in Parallel....they both work !!!!!
Answers on a postcard please to VERY Confused of Stoke on Trent
theconrodkid - 15/3/04 at 05:33 PM
you got 2 wires on ign light bulb holder,remember it goes through the bulb and earths via alternator reg
Alan_Thomas - 15/3/04 at 05:34 PM
Is your new lamp an LED type? I ask because on many altenators the ignition warning light needs to pass enough current to energise the field coils of
the Altenator. It then starts to produce voltage which rises and turns the Ign lamp off.
An LED may not pass enough current to energise the field coils.
However if your altenator is not this type the above is a load of rubbish
jonti - 15/3/04 at 06:15 PM
quote:
Originally posted by theconrodkid
you got 2 wires on ign light bulb holder,remember it goes through the bulb and earths via alternator reg
Mmmmm...Yeeeessss....and ?
And no its not an LED just a bog standard 4w Bulb....ta
Thanks Chaps both but , to my mind ,its bloody illogical, the only thing I can think is that, as it does indeed earth through the alternator, it may
indeed, as you say Alan be something to do with the current drawn by the bigger bulb and less current not triggering the earth path through said
alternator.
[Edited on 15/3/04 by jonti]
theconrodkid - 15/3/04 at 07:20 PM
ign bulbs are normally low wattage 2-4 watts
jonti - 15/3/04 at 07:32 PM
quote:
Originally posted by theconrodkid
ign bulbs are normally low wattage 2-4 watts
Correct !..........so.........the answer to the problem is ?
P'raps theres a resistor in the Diahatsu cir-trickery that compenstates.......I dunno...that may be the work-around I have to apply to get this
sorted though.
Unless someone has a better answer
[Edited on 15/3/04 by jonti]
stephen_gusterson - 15/3/04 at 09:46 PM
a really really bright 21w ignition light?
Youd never miss it coming on 
seriously - can you get a cct diag from the original fitment car and check it against that? Or use a ballast resistor if all else fails....
atb
steve
jonti - 16/3/04 at 09:11 AM
quote:
Originally posted by stephen_gusterson
a really really bright 21w ignition light?
Youd never miss it coming on
_________________________________
Actually ,as I thought I'd do a bit of competition with the car when its finished, I did think of having a big one (oo er missus) as well.
Alternative is to use a resistor I suppose.
theconrodkid - 16/3/04 at 09:25 AM
ive got the same alternator as you,works ok with the 2w bulb,sure its on the right terminal and alternator bod is earthed?