jabbahutt
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| posted on 6/8/08 at 07:05 AM |
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ignition light
any help on this appreciated.
I finally fitted the dash last night and wired everything up.
About 2 months ago I tested the alternator circuit, ignition light on and when engine starts it went out, fantastic
the bulb has a switched postive connection and one to the alternator
Last night all the warning lights work except the ignition light. I've tried another warning light, still nothing, put a mutlimeter across the
bulb contacts and there was on 0.1V
Checked the battery and it had run low, so put it on charge. This morning still no ignition light. Will the ignition light only work with a well
charged battery or should I be looking for something else?
I'd hoped it had something to do with low battery charge and the alternator having a high resistance or something(electrical numpty) but now
I'm starting to think it's something more awkward and that will probably mean removing the dash again which was a right pain to fit.
Any help on things to check much appreciated.
Thanks
Nigel
[Edited on 6/8/08 by jabbahutt]
[Edited on 6/8/08 by jabbahutt]
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02GF74
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| posted on 6/8/08 at 07:17 AM |
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your understanding is correct.
For conventional alternator and filament bulb wiring should be:
12 V - igniton barrel - lamp - alternator.
Once you have turned igntion on, the lamp should see 12 V and light up as the alternator side will be low. When alternator is running, that
connection rises to 12 V so the lamp goes out as there is no voltage difference across it.
Now you say you measure voltage across bulb - can you measure voltage on each side of the bulb? i.e. one probe on the bulb wire and other to a
ground?
If both show 12 V, then someting has gone bad with the alternator or wiring. You can disconnect the charge wire from the alternator and repeat - this
will identify the wires to the bulb, hopefully you will have colour coded them!
If both sides are 0 V, then it means the wire to the battery via the ignition switch has come adrift. You would need to trace that wire and fix
it.
Also check to see that the alternator body makes goo contact to ground - measure resistance between its body and 0 V of battery.
It has nothing to do with battery charge - even if voltage was down to 6 V, the bulb should glow albiet very dimly.
[Edited on 6/8/08 by 02GF74]
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jabbahutt
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| posted on 6/8/08 at 07:41 AM |
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Thanks that's exactly what I needed. Thanks for the great laymans explaination as to how to go about checking it and what I should be looking
for.
Will arm myself with a multimeter tonight and see how I get on.
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jabbahutt
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| posted on 7/8/08 at 06:53 AM |
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okay, hands up I'm a grade A fool. went into the garage and as per the really helpful list of things to check started with voltage at bulb.
12V at switched side so assume the problem is at the alternator side. Whip the bonnet off and I'd disconnected the lead from the bulb to the
alternator. Reconnect and all is well with this particular problem.
Cheers for the help though
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saigonij
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| posted on 7/8/08 at 07:03 AM |
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school boy errors are the funniest....
when i fitted my dash for the last time, i decided to neaten up the wiring.... the end result was the lower dial lights not working!!!! turns out i
had cut and taped an earth wire together thinking they were not required - was the earth path for the lights!!!! hehe
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omega 24 v6
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| posted on 7/8/08 at 11:30 AM |
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quote:
school boy errors are the funniest....
Ain't they just but not at the time. I've just spent 3 weeks on a "Schoolboy error" I knew it was something so simple as well
but could I find it could I Buggery.
All done now though
If it looks wrong it probably is wrong.
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