Alternator Warning Light Wiring

[dave368]

Hi Guys,

Really dumb question here, but I haven't been able to figure it out so I thought I would ask. I'm rewiring the car at the moment but I don't get how the alternator warning light on the dash needs to be wired. I understand that there is a charging circuit from the stud on the alternator back to the battery (via kill switch) and then there is a 3 pin plug on the back of the alt (I believe the alt is from a 3sgte).

One of these pins goes to the stud on the side, one appears to go to Accessory power and the other to the light. Is it as simple as that or have I got it completely wrong?

If it is that way, then what prevents the output from the stud on the alt lighting up the warning light on the dash?

I hope someone can help, I hate asking dumb questions!

Cheers,
Dave

[Cool1]

The wire from the alternator(Yellow?) should go to the light via a diode! The other side of the light should go to ignition!
So when the alternator is not spinning the wire you need(yellow?) should be at 0v completing the circuit for the light.
The diode needs to be wired so that the cathode is connected to the alternator and the anode is connected to the light!

That help?

[takai]

Ah, so thats why mine wasnt working properly. Stupid diodes. Although for the IPRA car im not quite sure why you are wiring up the alternator charge light

[dave368]

Ah, so thats why mine wasnt working properly. Stupid diodes. Although for the IPRA car im not quite sure why you are wiring up the alternator charge light

Thanks Cool1, that makes a lot of sense. I'll chuck that into the car tonight

As for needing one in a race car, have a chat to the Gav/Graeme Wilkinson sometime. This year at Wakefield they threw 3 alternator belts resulting in 2 DNF's and the only way they know that it happened is via the alt warning light and then the car stopping a couple of laps later.

Cheers,
Dave

[Cool1]

No problem mate.
If you need to know exactly how all the wires from the alternator connect up let me know.

[takai]

Ah, ill know from my water temp gauge. Throwing alternator belts tends to result in losing the waterpump too.

[dave368]

Ah, ill know from my water temp gauge. Throwing alternator belts tends to result in losing the waterpump too.

Fair enough, but the 3sgte uses the cam belt for the water pump

[takai]

Yeah, very true. I hadnt thought about that.