Detecting electrical short?

Detecting electrical short?

arggg..

I think I have a short in my electrical system somewhere. I run a 2-3yr old optima yellowtop relocated to the trunk, with power wire fused at 70A 18" from the battery. All aftermarket electrical components has a inline fuse less than 12" either at the engine bay distribution block or the battery..

The story starts 2 weeks ago when I left my driving/fog lights on about 5-10mins (not a big deal w/ a deep cycle battery) at a parking lot and the engine wont start so I had to bum a jump start from someone. That night I went through the engine bay with a flashlight to look for the short with no luck, I left the door open so the dome light was on. Next day - wont start, bum a jumpstart from a neighbor. So this past weekend I didn't start the car at all for about 36hrs and the battery had only 10V on it so the engine wouldn't start.. My friend came over and we re-done the connection to the amp, and check the alarm system - no visable sign of a short. But just yesterday I was at a gas station, spent <5min fueling up and forgot to turn of headlights (i've done this numerous times before with no trouble) and the engine just barely started...

What can it be? I am pretty sure there is a short somewhere. I dont think it can be the battery because as I said previously, I have a optima yellow (yes the terminals,/connections are VERY tight). I dont think it can be the alternator because the 96-97 models got rid of the alternator probs, cant be starter because I had it replaced 20K ago and it stars right up as long as I start the engine every 24hrs or have it jumped.. I'm going to bring my car in to autozone to have the alternator checked and battery tested (I can only imagine the look on the face of the guy @ autozone when I ask him to test a optima yellow)..

Any suggestions?

That make these little short detectors (Autozone may have them or you can make your own). Anytime there is current flowing through a piece of wire, doesn't have to be a whole lot - it will generate a magnetic field. From the sound of your situation - sounds like it could be a single significant leak or a bunch of smaller leaks. The detector will pick up on this field change and have some indicator (buzzer, meter, etc.) to help you pin point it. Principle is the same as using a compass to map out magnetic fields (most people should have seen that in H.S. or in College Physics or Life Science courses).

I'd start with all the modifications to the car's original electrical system (audio, battery relocation, etc.) and work outward. Electrical shorts are some of the toughest to find. You could also use a ammeter or DMM to figure out how much juice is being leaked out (connect to the negative battery terminal post and negative battery terminal, then loosen the negative terminal (keep the probe connected to both post and cable to keep the ECM keep alive memory going) completely - measure the resulting amp drain on the system. Should be on the order of hundreds of milliamps - any more and your system will drain itself pretty quickly.

I have the battery disconnected for the night.. I have been taking voltage reading for the past three nights, there is usually ~12.2V in the morning. I will see if there is a reduce in voltage drop with the batt disconnected.. so far I have tried pulling fuses to my aftermarket accessories (alarm, remote starter, foglights) but the problem is still present.. About a month back the car would start in a second with no problems, recently there is a noticeable increase in cranking time and it seem to struggle just to start.

I wont have anytime to get it checked out until friday.. I am looking into short circuit detectors but i cant seem to find one for less than $30:sad: