I think I have a short somewhere because when I went out today to go somewhere my car wouldn't start and the battery was dead. I have a multimeter that someone gave me but I've never used it. I want to figure out how to measure if there is a draw on the battery and how much. I've been told that the computer and alarm pull around 20 - 50 milliamps so anything above that will mean somethings drawing power. Also, if you can tell me how to check if the battery is good or not. Once I figure out the power is being drawn then I can get into the fuse box and figure out where(fun)

I bought the battery about a year ago so it should still be good but I have heard some horror stories about Optima batteries. Hopefully, that isn't the case since that bastard was expensive!

This is the multimeter I have:



Thanks!

John

 

First off, are you sure the battery is truely dead? i had a problem starting my car awhile back, and it turned out to be that the starter just had a loose connection. if you could provide more info on your problem? does it just click rapidly when you try to start? does it do nothing at all? do the lights work? radio work?

i would maybe first check the batterys voltage [should be about 12v using the multimeter], and/or take it to have a load test (free at most places). if the battery is good for sure, then start shootin wires.

 

Just got off the phone with my buddy. He knows how to use one of these.

Battery reading with engine off: 12.37
Battery reading with engine on: 14.26

Reading with positive lead disconnected, MM in line set to 10A and car off: -0.12A

He says the battery readings are fine but that the in line reading is high. He says that my car is pulling 120 mA shut off. Ford says that 50 mA should be max. Somethings pulling 70 mA or more. Would a bad ground do this even with the car off and the accessories off?

Also, I installed some white face/reverse glow gauges and my seat belt warning chime started working again. Could this be part of the problem? This problem started right after I installed the gauges. I probably didn't ground them right. Could this be the problem even though the headlights where the gauges are connected to aren't on?

John

 

^yes definitely. i could be arcing everytime you try to crank it. do your gauges sweep when you try to crank it?

 

They do sweep when I turn the car on.

Took apart the dash and reinstalled the gauges. I measured at each step to see if there was any difference but I got the same reading. 13.58 set at 10A. That's 135 mA right? The battery is holding a charge. The alternator is charging at the correct voltage.

The only thing I can think of is I pulled the ABS and Air Bag bulbs out of the back of the cluster but I don't think this would set off a current draw. Maybe the Mach CD player? I don't really have time to go through each fuse until the weekend. When I do I'm going to have to unbolt the strut tower brace because the fuse box lid hits it and I can't get it open.

This Blows!!!

John

 

you should hook the meter up inline like you were doing and then start pulling fuses one at a time, once you pull the one that makes it drop into your .050 spec you know which electrical system to diagnose.

 

something is grounding. do livefast says and you'll find the ground.