Where do I start with a power draw?

Every night I have to disconnect my battery due to a mystery power draw. I have no clue where to start looking. Any advice would be greatly appreciated. Mike

 

Hello Mike,
You could hook up a ampere meter on the feed from the battery and watch the reading as you pull the fuses one by one. When you see that amps go down near zero you just read on the fuse box what things are powered from that fuse, and go from there. Keep in mind that varius things like clock and ECM (if its a modern car) draws power all the time so meter should actually never show zero.
Christian

 

I can only tell you what I do. Take the alternator and regulator to the auto parts store and get them checked, they are the "usual suspects". This is the first thing to do. If they are good, then you can drive yourself nuts doing all the things suggested above, and likely find it.
Here at Auto Zone they can check both, I just had them done a month ago. They may be able to do it on the car, not sure, but I had mine off. I had a bad regulator.
Good luck,
Mike

 

Try simple things first, I would wait till it gets dark and look for some lights that are left on, trunk light, ashtray, glovebox, under hood etc. if you have an aftermarket stereo, check to see that it stays off, or if you are running an amp, that its off.
Otherwise, disconnect your alternator and check to see if the battery is still charged in the morning, if the battery stays up your alternator prob needs a diode/replace or repair.

Like someone else said you can try eliminate each electrical device by pulling fuses or using a multi meter, my 2 bits, good luck Gord

 

This is the right method, but what I like to do is use a cheap piezo buzzer from radio shack instead of an ammeter. Disconnect the radio if it is one of the newer ones, and pull the interior light fuse since you'll have the doors open. Disconnect the negative battery cable, and put the buzzer inline between the negative cable and negative battery terminal. If you have a draw, the buzzer will make noise, disconnect components/fuses until it stops making noise. Whatever you disconnected to make the buzzer shut off is the source of your draw. It's a lot quicker than using a meter since you won't have to look at the meter every time you disconnect something.

 

I'm betting a voltage regulator is the culprit.I'd try Larry's idea and then unplug the plug to the voltage regulator 1st..

 

good one :TU:

 

i recently had a similar problem---battery would be dead about every other day. i had a 10 disc cd player under back seat. (F-150 p/u) during a change of disc the player locked up somehow (unbeknowns to me) and the mechanism that changes the disc kept on trying to work even when the key was off and out of the ignition . using my electrical tester i pulled the positive cable from the battery clipped the tester wire to it and clamped the ice pick end of the tester to the hot post of the battery and began pulling fuses one at a time until the light went out in my tester. there are probably several different methods here but this worked for me.

 

Thank you all. Looks like I will have to pick up a voltage reader. I really had no clue where to start and I now know. Cheers, Mike

 

Resisitors for meter movement on my guage. (Factory)

Is it hard to crank over, when starting?

When you get your meter get a good one; they come in handy around the house and all.
I'm assuming you know how to use a meter and leads, Red is (+) while Black is (-) Be on DC volts on the meter.

1)Start with the battery and you should measure 12.5vdc just sitting there.
2) Fire the puppy up and start the vehicle, now measure the battery Voltage across the battery should now be 13.5vdc to 14.5 vdc (Let it run for a bit)
3) Turn the vehicle off for five/ ten minutes and go back and measure your voltage. Should be ~ 12.5 vdc

That's a start for you.
Let us know what you find.... OK?
Thanks

Problem can be many things, drawing current and loading down the battery.
<hr>
On another note on my 71 GS:

Anyone know what the wire wound resistor values are on the guage for Generator, parking indicator, Fuel, Temerature and oil?
I have three of them.
I know they are for the the meter movement and two of them measure ~ 38 Ohms and the other for the Hot Cold meter is 144 Ohms.
What should they be?
Is this correct?
Can I replace them with precision resistors?
Thanks again

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