Alternator & Warning Light Question

[s6otty]

Well, she runs!

94 Chim, up and running, just trying to sort the dash lights/gauges out, but the output from my signal wire in the alternator is only 7 ish Volts, although the charging output is correct, I was expecting 12-13 Volts?

The LED seems to have 2 resistors across the back of it, do these provide a voltage differential for the LED to light up when the car is not running/charging.

Also, my Oil pressure LED doesn't seem to work, is this just a live to one side, and a negative from the oil pressure switch? Is there any way of testing the switch?

Thanks in advance,

Scott

[Hedgehopper]

LEDs are polarity sensitive and therefore only work when the wires are the correct way round.

[s6otty]

I believe I have the wiring correct, and the alternator does charge.

When I switch the car off the light comes on for a second or two then goes out. It does not come on when I turn the ignition on, I would have thought it would?

I think the resistors are there to provide the path from the battery to excite the alternator.

Scott

[Hedgehopper]

My car did the same. The ignition warning light only came on briefly as I turned the ignition off, it didn't come on at all when the ignition was turned on. I reversed the connections and all was OK.

[s6otty]

So it should be on with the ignition until the car is started?

I'll swap it over and give that a try.

Am I right in thinking the +ve of the LED is the "car" side, and the -ve the alternator side?

Still trying to get my head round why there are 2 resistors cobbled in across the LED wires!!!!

Thanks

Scott

[Hedgehopper]

On my car the brown/yellow wire goes to the neg. side of the LED and the green wire to the pos. If you look at a LED closely you will see a 'flat' moulded into the shoulder of the lens, this denotes the negative terminal. Also, if you look into the glass of the LED you may be able to see two 'filaments', the smaller one is the other end of the neg. terminal.

Hope this helps.

[s6otty]

Morning!

I have come to the conclusion, that although it charges correctly, there must be an issue in the diode pack/sensing circuit in the alternator. It can't be anything else!


Thanks for you input.

Scott