when I first decided to fix this thing up i had problems. Before it wouldnt start, now when the battery is fully charged it will start and run fine, but the next day it will be completely dead. Bought a brand new battery and hooked up the neg terminal and tested for drain with the pos terminal, and it would arc a little bit. didnt hear relays click, but unhooked both anyways, still arcs. pulled every fuse, still arcs. Can someone please help me locate this battery drain. BTW its an 89 f150 4.9l i6 2wd

 

To me arcing alone, doesnt mean you have a draw. I'd get out the ol volt meter and go to town

 

then why would it die over night?

 

Does it with all the fuses pulled?

 

I think what he's saying is that seeing an arc is a poor way of determining if there's current draw.

You really need to hook up an ammeter between the battery and the rest of the system to actually measure the current flowing out of the battery. Most multimetrs have a ammeter function, though you may need to move the test leads to a different socket.

A few milliamps draw is normal (the radio and ECU both use a small amount of power to keep their long-term memory intact.) Anything over 500 milliamps would be a concern, I think.

After that it's a case of disconnecting circuits until the current draw measured at the battery drops to normal.

A wiring diagram is going to be important for this.

 

well the radio is not even hooked up right now, just loose wires. and where should I place the meter to test it? Do you have a wiring diagram?

 

You would place the meter between the battery's + terminal and the cable that's normally attached to it. Do not turn the ignition on with the meter in place.

I do not have a wiring diagram. You're going to have to either get the factory service manuals (best,) or a Cilton's, Clymer, or Haynes with a diagram in it.

 

X2 that's the way to do it. You should be able to eliminate the draw by pulling fuses as all factory circuits should have protection. If not, first check any aftermarket work ( radio, lights, trailer wiring ) then track from the battery disconnecting and connecting any power leads until the drain drops below 500 mA. It would help to look for other electrical issues. Like dim lights, speaker buzzing, accessories or lights not working and check that system first.

 

Are you sure your alternator is working properly? I had a same situation, always had a dead battery in the morning. Turned out my problem was bad alternator. Also check your battery cable going to starter and your ignition switch inside your column.

 

just unhook the battery at night until you find it...

to check an alternator quickly? Key ON a metal wrench should stick to the alt's pulley from the magnetic field...

Key OFF it should NOT... if it does the alternator is staying energized... this does happen sometimes when alts go bad....