Alternator Warning Light

[Thrashed]

Hi Guys

 

Alternator issues seem to be a hot topic at the moment and I need help with mine.

 

I have sapped rom a Bright 6 warning light set up 2nd unit that had broken on me) to Europa LED individual warning lights (http://www.europaspa...arng-light.html)

 

All of the LED's work fine except for the battery warning light which will not switch off.

 

I am running a premier wiring loom in a zero with a pinto and a denso alternator that looks like the attached and is wired like the attached.

 

So far I have tried the following:

• The battery with ignition off is showing 12.4v on the multi meter.
  
• With the engine running the volt meter in the dash reads 14v.
  
• The voltage at the battery with the engine running is showing 14.3v on the multi meter
  

The dash warning light just stays on.

 

Next I tried connecting an old indicator bulb holder direct to the alternator, nothing at all with the ignition on or engine running.

 

I then removed the dash LEDS and replaced with the indicator bulb and again nothing with ignition on or engine running

 

I known the indicator bub is working as I connected direct to the battery an it lights up.

 

Now, the only alternation to the wiring I have made is adding a 1k resistor into the LED wiring so that the alternator would work.

 

I have continuity tested the wires from the alternator to the dash. For the Black wire (12v switched live) I get continuity at all points of the wiring.

 

The Blue wire I get continuity from the alternator to the dash but I then have a connector to the dash warning lights and I get a reading of 17XX but no continuity beep?

 

I replaced the wire from the loom to he warning lights and got continuity but still made no difference to the light going out.

 

I have the LED light wired as per the Premier Loom instruction with Blue on side and Black the other.

 

I think the Alternator might be duff, but before I start pulling it out of the car and buying a new one I want to make sure it is nothing I am doing wrong on the wiring.

 

Any ideas gratefully welcome

 

Thanks

Steve

[Guest peter2b2002]

LEDs are diodes that might be your problem only allow current to flow 1 way

peter2b

[maccavvy]

yes its most likely an led issue. im sure someone found a way around it.. I cant remember who though

[Thrashed]

Hi Peter, good call butI did check this too, if I switch the wires on the LED terminals just get no light on either ignition or engine running.

[Thrashed]

What confused me is that if bypass all the car wiring and have 2 new leads from the alternator it still does no work on either a standard bulb or LED?

[alanrichey]

Might be teaching grandmother to suck eggs but as I understand it, the logic works like this:

 

One side of the Warning light is 12V+ ignition switched, the other side is connected to the alternator output. So when the ignition is switched on the warning light goes on as the alternator output is nominally 0V. Once the engine starts that small current flow is used to excite the alternator (unless you have a self-exciting one) so that it starts to output a voltage. If the alternator produces 12V+ it would then balance the 2 inputs to the light so it would extinguish. Unfortunately, as you have proven, your alternator will actually produce 14V+ so that results in a -2V+ differential voltage across the light, which will cause it to stay illuminated, either dimly or fully on depending on the type of light. So as previously stated you need to put a diode into the circuit between the alternator and the warning light so it will only illuminate if there is a +ve voltage differential.

[blue]

Get a length of wire put a 12v bulb in the middle connect one end to alt and the other end to +12 on battery. Start car if light goes out - wiring prob if it don't then it's a alt problem

[Guest chris brown]

If you want to use a LED for the ignition light then the way people have got around it is to wire a small low wattage bulb in parrerell with the LED

[Thrashed]

Alan, I have put a 1k resistor inline from the alternator to the LED light. Are us suggesting I put another one in? If so where would I put this?

[Thrashed]

Blue, I have tried this with both terminals 1 and 3 on the alt, with both a standard bulb and a separate LED. When I do this I don't get anything, switch ignition on and no light, start the engine and no light?

[alanrichey]

Alan, I have put a 1k resistor inline from the alternator to the LED light. Are us suggesting I put another one in? If so where would I put this?

Not a resistor, a diode. I use these http://www.ebay.co.uk/itm/Durite-In-Line-Diode-with-6-3mm-Blade-Spade-Terminals-10amp-12-24v-DC-/400536132610?pt=LH_DefaultDomain_3&hash=item5d41d05c02

[Thrashed]

Thanks Alan, were in the wiring would I put this? On the Battery light wiring from the Alt to the light and would I remove the resistor or keep that too?

 

Thank

[blue]

Can I ask when you put bulb from small term on alt to direct battery positive does the bulb light up - you won't need ign on yo try this.

If the bulb lights up then start car and see if it goes out if it don't light up at all then diode in alt has gone

[alanrichey]

Thanks Alan, were in the wiring would I put this? On the Battery light wiring from the Alt to the light and would I remove the resistor or keep that too?

Yes, I just disconnected the female spade alternator feed wire from the warning light and plugged that into the diode and plugged the female spade terminal on the diode directly onto the warning light.

[Thrashed]

Thanks Alan. Will give that a try and see how I get on. Will keep you posted.