Alternator light stays on

[cjrpony]

I have been trying to figure out how to make the alternator light work properly but so far no success

I have the New Vintage 7 LED indicator panel and have all the lights working except the charge warning lamp.

I have a 560 ohm resistor hooked up in parrallel with the light. I have one end hooked up to the brown IGN FEED wire in the Ron Francis harness and the other to +12 switched.

The light turns on when the key is turned and goes out while the engine is cranking. One the engine fires, the light dims a little but does not go out. The volt gauge indicates 14 volts so I believe the alternator is charging.

If I unhook the IGN FEED wire while the engine is running the volt gauge drops to around 12 volts, so I believe the exciter circuit is working.

I have heard that LED's don't function properly in this setup. Can anyone shed more light on how to get this to work properly with the LED?

Thanks, John

[JKleiner]

Put an incandescent lamp in parallel with the LED.

I first set mine up using the incandescent indicator with 510 ohm resistor in parallel and everything worked fine. When I substituted an LED for the incandescent bulb things went wonky much like yours---it was still charging (thanks to the resistor) but the indicator wasn't functioning properly. I made the LED indicator work properly by also wiring the incandescent lamp in parallel. It remains in the circuit tucked into the harness out of sight behind the dash. I think the problem is caused by the one way flow of current thru an LED and the fact that the charging system excites by an imbalance between alternator and battery.

Jeff

[cjrpony]

Thanks Jeff
I had actually seen your suggestion in another thread. I went ahead and tried it and it does work.

Does anybody have a proper way of wiring this up? I am going to ask New Vintage for their suggestions also.

Otherwise I guess I will run the extra lamp down to my underdash panel and put it there for easy access.

[Bill Lohmiller]

I make no claim to this being "proper" but I put a resistor in series with the LED. (This was on an LED that already had a built in resistor to run on 12V) I kept the "in case the lamp fails" resistor in parallel in place. Sorry I don't remember the ohm's on the resistor added to the LED but I had to try quite a few before I got to one whereby the LED was bright enough to see in the daytime but was "out" enough in normal operation at night.

What I mean by that is if it is pitch black out and there is no other ambient light, I can still see a faint glow during normal charging, so not perfect as such. Perhaps a bit more fine tuning of the resistor would make a difference but it was close enough for me.

BTW, at the time I did a LOT of internet search for the "proper" solution for this and the answers as such were all over the place -- which was a bit surprising given how many folks were/are trying to use LED's for all their function and warning lights.

HTH or at least points you in the right direction.
Bill

[cjrpony]

Thanks Bill, I have an email into New Vintage. Hopefully they will point me in the right direction. Maybe they know the correct resistor to use. I request a wiring diagram also, so will post it up if it works.

John

[cjrpony]

New Vintage replied but they really didn't have a solution. Some searching on the internet came up with some circuits that involved diodes and brigde rectifiers.

I ended up just going down to radio shack and buying a mini 12V incandesant lamp (pn 272-0345). I popped out the led and the bulb fit the New Vintage indicator housing almost perfectly and worked with the my current resistor in parrallel.

So no solution to using an LED but I don't have an extra charge light hiding in my dash either.

[Avalanche325]

Couldn't you put a resistor in parallel? A bulb is a resistor, so to speak.

[cjrpony]

Originally Posted by Avalanche325

Couldn't you put a resistor in parallel? A bulb is a resistor, so to speak.

I have a 560 ohm resistor in parallel already. It didn't work with the LED. Jeff is correct, a LED is a diode, so that causes it not to function correctly as an idiot light due to its one way nature.

Here is pic of the New Vintage indicator panel on the dash. I have since finished up the rest of the switches and wiring and am getting ready for 1st go-cart

[SeanHM]

Thanks for bringing this up. I have the same issue. Think I'll try adding the bulb behind the dash.

[Epicenter]

I chased the same problem for quite a spell until I admitted failure and begged for advice. I put the bulb in line and couldn't believe it was that simple. This site is priceless for these kind of tips!

[VdubJoe]

Yep just like wiring up a alt on a vw. Have to wirein a small 12 volt lamp. Otherwise it will not charge.

joe