Truck keeps dying?!? Need help fast

[Deasel]

Hey, so I need someone's help real bad. I have a 98 4.0l v6 ranger and the battery seems to be getting drained. I've replaced the battery, alternator, 175amp mega fuse going from the alternator to the battery, and I also replaced the terminal connectors for better connection. I have ran out of knowledge and can't figure out what is causing the problem?!?! Does anyone know what I can do?

 

[RonD]

Yes.............get a Voltage Meter

Select DC Volts, 20vDC if available on meter selector

New battery should show 12.6v to 13.0volts with Key off, if battery is drained it may show less voltage, but get the exact voltage and then do the rest of the tests.

Now test alternator wires, Key is still off
Black wire on voltage meter should be Grounded, on battery(-) or engine metal

Use Red meter probe to test the wires.
Larger wire on the back of alternator(B+), held on with a nut, should show same as Battery voltage.
If not then trace wire, it is broken or new MegaFuse is bad.

Unplug the 3 wire connector on alternator
There will be a Yellow(white stripe) wire, it should also show Battery voltage, if not then ALT fuse is blown, 15amp or 30amp, in engine fuse box.

Now test the ON/OFF wire for alternator, Light Green(red stripe) wire, it comes from the Battery Light in the dash, this turns alternator on and off.
Should show 0 volts with key off.
Now turn on key(leave engine off), test wire again, should show battery voltage now.
If not then check cab fuse panel, 7.5amp fuse, often #15 but check owners manual.

There is also a White Field wire, it should be a short loop wire, from 3 wire connector to another terminal on the alternator, unplug it as well and check that wire is not frayed or "hanging on by a thread".

Plug connectors back into alternator if all wires and voltages check out as OK

Start engine
Battery should now show over 14volts, but under 15volts, this higher voltage will continue until battery is recharged from starter motor drain, so a few minutes.
If voltage is not high, above Battery Voltage, then alternator is bad, take it back.

After initial Recharge voltage will drop down to 13.6v approx. at warm engine idle, 650-750rpm, this is the maintenance voltage, keeps battery charged but low enough to keep fluid in battery from "boiling away".
Turn on all the lights and heater fan to high, voltage should drop and then come back up to 13.6v, that's the voltage regulator working as it should.

 

[naford]

Is it draining while it is sitting or when it is running? If when it is sitting. Then you need to use the amp part of the meter and pull fuses until you find the drain.

 

[pjtoledo]

how old is the battery?
does it die while running?
is it dead after sitting a while, or overnight?
has the vehicle had long periods of time between use, as in does it sit all week then is used on the weekend?
any aftermarket sound, alarm, lights installed?