alternator warning light

looks right just make sure you get side of breaker that goes cold when tripped,... obviouslyGreenGables

I just figured out that it will not work! The battery will push back down the line and provide power to the relay. I need a way to isolate the circuit breaker from the battery.Sony XAV-A1 HU, RF P4004 AMP, RF P3001 AMP, 2 RF 10" P1S410 Subs, LA S2.35.2 Dash Speakers, LA S2.525.2 Door Speakers, RF FRC3268 Rear Speakers

http://www.bcae1.com/circuits.htm Little more then halfway down. "Blown Fuse Indicator"

awdeclipse, I have been looking at that page off and on all day and I can honestly say I am baffeled by it! I am not really great with the elctronic circuits as of yet and I am stumped as to really even start building that circuit!Sony XAV-A1 HU, RF P4004 AMP, RF P3001 AMP, 2 RF 10" P1S410 Subs, LA S2.35.2 Dash Speakers, LA S2.525.2 Door Speakers, RF FRC3268 Rear Speakers

Well I always go about things one of two ways. Trying to understand it before building it, or just following the circuit and figuring it out later if it doesn't work. Here is another site I find useful to help break down the basics of transistors. If anything the site usually serves as a quick reference for myself as I work with transistors few and far between these days. BJT Switches Overview

If the load-end of the breaker has loads of a few amps or more, a 2W-3W bulbs across the breaker should suffice. Otherwise a 12V LED (LED with resistor) for smaller loads, or maybe add a resistor from the CB downstream (load) end to ground. I am curious - this is not a battery-alternator CB? What does it power? PS - re-reading it sounds like the battery to alternator... The problem is you will normally be sensing a mere change of 1-2 Volts if the fuse/CB opens. (13V is the alternator fails - but its charge lamp should come on for that....) I recommend a voltmeter, then you can see how good your system is under different circumstances (overnight voltage, cranking, overcharge (>14.4V long term) & undercharge (under 13.8V at reasonable revs).