So yesterday, I thought I had a bad battery (4 years old and came with the truck when I bought it used). After 1-2 days, it was unable to start the truck. After replacing it with a new one, I drove about 30 miles with no issue. This afternoon, it was -totally- flat. I mean, the starter relay chattered a half a second then went silent.

I thought of 3 possibilities. A.) Alternator not charging B.) Phantom load somewhere and C.) Dome light staying on.

A.) Engine not running but ignition on, battery reads 12.4 volts. After starting, it goes to 13.7 to 13.8 depending on RPM. No codes or CEL, so that's not a prime suspect.
B.) Something, somewhere, is not turning off when it should. Sans time spent out in the *bleeping* hot sun tracking it down, I don't feel like chasing that down right now.
C.) Door ajar. Every once in a while, I get two beeps when double-clicking the lock button. It happened last night when I retired, but the dome light didn't stay on. So I doubt it's that either. My previous '02 had at least one bad door switch, but I never had any issues related to it.


So other than B, are there other possibilities I should look for? 2009 4 liter.

 

12.4v should be OK to start but new battery should be 12.8volt at least

Above 13.5volts running is OK, but just after starting it should be 14.5volts then drop down to 13.7volts after 5-10min of running, so may be time to change alternator, very common when a battery fails

If engine will not crank then either starter is drawing too many AMPs or the Positive or negative battery cable are corroded, clean BOTH at BOTH ends
12.4v should crank just fine
If possible have volt meter hooked up and watch voltage while cranking engine over, should drop about 2 volts, but no more, so 10.4v

 

Put it on a trickle charger overnight to make sure it would start this morning. It did with no issue. 14.5v after a few minutes of running. I'll leave it parked for now to see what happens.

 

Test test battery voltage after it has sat a few hours, then test again after it sits over night, write it down
If its dropping then disconnect either battery terminal and let it sit a few hours and retest, if its still dropping your new battery has an internal short, not that uncommon, get it replaced

You can't get a true voltage reading from a battery after its been charged, by a charger or by the alternator, it has to sit a few hours to get true voltage reading

If voltage stays the same after disconnecting one terminal, but was dropping with both cables connected then you do have a higher than normal drain
Most volt meters have an AMP setting
Key off, doors closed
Disconnect either battery cable and put AMP meter on open battery terminal and battery cable, will show you the amps being used
0.03 to 0.07 amps is normal
0.1 and up is not
Open engine fuse box and pull out the larger rated fuses, i.e. 30 to 60amp
See which one causes amps to drop to under 0.1
This will help you chase down the drain

 

After sitting for 6 hours, voltage is down to 12.05. Ammeter across disconnected ground cable and terminal is 23mA.

 

Pulled every fuse in the main block, as well as every relay. Still 23mA.

 

23mA is 0.023amps which is low, I assume you don't have keyless entry(Fobs), so just radio and computer are the draw

Your new battery is bad, leave it disconnected and see if it drops more, that would confirm self-draining battery

 

Yes... keyless fobs. I'll check it again (it's still disconnected) in a couple hours.

 

After being disconnected for 3 hours, the voltage is up to 12.26. Still 23mA draw.

 

Are you sure its not 2.3mA?
So 0.23amp

23mA drain would take 4,350 hours or 6 months to drain a 100AH battery

 

Fluke 87 reads 0023 mA.

 

Not making any sense

Google: Using a Digital Multimeter to Check Amperage | ACDelco TechConnect

Video using a Fluke 87 to check amps and to test fuses in the Fluke meter

 

I know how to use a meter. I've had the Fluke for 26 years.

It ain't rocket surgery. 0023 mA means..... 23 milliamps.

 

Just went out to check it. 4.24 amps now.

Pulled #3 (40a) fuse from main distribution box, and it dropped to 21 mA. So... that feeds the fuse box in the cabin. Tracked it down to fuse # 28, 20a.... 4x4 Module Feed. Pull that one, and the amperage drops to normal.

So now to track down why it's pulling power with the ignition off.

 

Good stuff

So its an intermittent draw, wasn't trying to diss you, it was just the 23mA draw didn't make sense to kill the battery, 4.24amps WOULD suck the life right out of a battery in a few hours, lol

I assume its a 4x4 2009 Ranger

Just a heads up, the 4x4CM(Control module) was a known issue from 2001-2011 on 4x4 Rangers, not for drawing power specifically, but for not working when driver wanted 4WD

Yes fuse 28 is Hot all the time

The 4x4CM is behind the radio from 2004 to 2011 on Rangers

 

For now, I'll just jerry-rig a bypass for that fuse. Reroute the circuit to an external fuse, then a SP switch I can toggle on and off when I get in and out.

 

Just as a heads up, 2004 to 2011 Ranger used the Smart Junction box(SJB) it behind the cab fuse box, well cab fuse panel is part of the SJB

The larger connectors on the SJB can corrode

Image here: https://i1.wp.com/sparkys-answers.co...0/DSC09929.jpg
And here: https://i0.wp.com/sparkys-answers.co...0/DSC09930.jpg

Easy to have a look

 

Leaving the fuse out for the offending module doesn't seem to affect driving. All I can see is the 4x4 and 4LOW lights in the dash stay lit, but the transfer case is not sending power to the front axle.

 

So I took time of during the hottest part of the day today to install a temporary fix.

I took the fuse out, routed the circuit through another fuse holder and through the contacts of a basic relay, and back to the other jaw of the fuse holder. I then found a circuit that was on the ignition, tapped off the protected side of it and used that power to feed the coil of the relay.




Pull the cover off the fuse panel, hook up the three power wires, ground the relay coil.....


Totally inelegant. Wholly hacked up. Completely bootleg. And absolutely hill-billy. But it does work. Coil pulls contact in when key is turned on, energizing the screwed-up module through the contacts. And when the key is removed, the coil is de-energized, shutting off power to the module.

Will suffice until I can get the module replaced.

 

Looks.................interesting, lol................good work