I am in the process of wiring. I am using an AC Delco 12SI 3 wire alt. I need to wire a 15 ohm resistor parallel to the charge light. Could someone please tell me what to buy. How much watts etc. I am just about at the end of my rope. I bought some at the electronics store those things get too hot for my liking . I know the wiring up to that point is correct since the light does come on with switched current and goes off once the motor starts. I would like to have the resistor in the circuit and not have to worry about the spare bulb. Thanks
The wiring seems to be taking me forever. When I add wood the progress is stark and the stuff from the cooler goes down easier, the wiring is the stuff headaches and @%$&^^ are made of.
Solo,I looked in every one of my electrical guides(street rod wiring books) and don't see anywhere that a resister is used parallel to an idiot light.
Why do you think you need this,and what type of GM alt are you using,an external regulator,or internal?
Are you also using a voltmeter or ammeter or just the light?
He has a 3-wire, it needs a ballast resistor paralleling the bulb to bleed down the voltage, or the light is always on dimly, and if the light fails, it looses output.
The exciter lead needs some resistance. If it is at full 13.8V it defeats the remote sense function, and can cause some ignitions (msd in my experience) to run on. I assumed it was a result of the field being excited backwards, through the sense lead. (could be way off, never really tracked the cause down. Replacing the light, and ballast fixed problem.)
The system will operate fine without the resistor.
The resistor is made to shunt the bulb in the event of a filliament failure, and keep the system running. If you don't have a resistor, and the bulb opens, the charging continues as long as the engine is running, but next time you start it, you will have no field startup in the alternator, and no charging.
Be sure you use the correct bulb, the resistor value changes with the resistance of the bulb. #57 lamp needs a 25 ohm-5 watt (in my experience) Use a wire wound, metallic film is not going to hold up. http://www.parts-express.com/pe/pshowde ... ber=015-15
Shipping is going to be more than the part.