hello all

I have a 2010 ford ranger 2.3 motor. I have a battery draw of .27. I traced it to fuse number 11. In the book it reads as the (passenger compartment fuse panel "logic power"). What can i do after this point what does exactly this fuse for, and how do I solve it? Any help would be much appreciated.

 

How did you narrow down the draw to f11? I'm staring at the wiring diagram. This is going into the deep end for me. Might want to double check with Ron..
anyway, l think logic power is referring to a logic switch. Something like a circuit board that turns other things on and off.
so, power into switch on f11. Directly downstream is 15a f12 for factory sub amp. And f17 indicator flasher relay
I would pull those two fuses one at a time. See if it kills your amp draw. FYI I'm no expert. Either way I would stay away from f11.. test something wrong u could cook components.

 

I used a multimeter attached in between the negative terminal and the cable. I set the meter on 10 amps and it was showing a .227 draw. At that point I began pulling fuses to see which one decrease the draw. It dropped on the fuse 11 the logic power fuse. I pulled all of the fuses to see if there was another, however it was the only one. When unplugged the connections of the wiring harness connected to the fuse panel I also lose the draw. At that point I reattached the negative battery cable and unplugged the connections. I took the multimeter and tested each wire with the corresponding prongs to narrow it down even farther. That's where is gets strange. I do not find the draw by testing each connection in the plug. Could it be a bad fuse panel?

 

Sorry for the delay didn't see this post until now, because Shineonchef replied to it

F11 would be internal power for the SJB(body computer) so not much you can check on it, but................
You do need to test amp draw after vehicle has been sitting with key out and doors closed, for 30 minutes, the SJB stays "awake" for 20-30min after key out/doors closed, so you need to wait for it to go to "sleep"

At that time you should see amp draw of .03 to .08, .08 if you have keyless entry because it needs to stay "awake" to receive FOB radio signals

SJBs are known for getting corrosion on the connectors, these are easily removed to check for corrosion
You need to remove the passenger kick panel to see the full SJB, cab fuse box is part of the SJB
Then you will see the large connectors, there is a lever on each one that you will lift up and that pushes the connector up and away from the SJB allowing you to pull out the connector and inspect its pins and slots
Corrosion would be obvious


Batteries can become self draining at any age, even brand new
Unhook 1 battery cable, battery should sit for an hour if it was just recharged by alternator or external charger as it will have a false high voltage
Test battery voltage, WRITE IT DOWN
Retest battery voltage at minimum 4 hours later, longer is better
Should read EXACTLY the same voltage

If voltage is lower battery is self draining, has a shorted Cell inside, no fix, replace battery

 

Thanks for the help Ron. I did let the truck sit for more then an hour befor I checked anything at all. Those large connectors with the lever, once disconnected I lose the draw. I tested each wire with the corresponding prong and fond no draw at all. No sign of corrosion on the connectors. When they are plugged back in the draw comes back. I have not pull the fuse panel all the way out yet. Would there be corrosion on the back side of it?

 

Ron, so the smart junction box would called the body control module in another brand? Question 2. The ignition switch wakes up the pcm. The pcm uses the can to wake up the smart junction box and other modules. The modules read sensors and switch things on and off.... ??? When you shut off the ignition does the pcm put the other modules to sleep? Or do they all time out on their own?

 

The PCM is unrelated, it is off with key off, it does have a KAM(keep alive memory) power draw, .02 amps, like the radio does, .01 amps, to keep clock and pre-set stations in its KAM

The SJB is what is "awake" or "asleep" after key off, some models keep power going for power windows after key off so you can roll up or down a window with key off, called "accessory delay" this is usually turned off when either door is opened
Then a "battery saver relay" circuit is what stays "awake" for 20-30min, if a dome light or glove box light was left on, it would lose its 12v after 20-30min to "save the battery"

Yes, SJB is the Body Control Module, Rangers used a GEM(generic electronic module) for the same functions, 1995-2003
SJB was 2004-2011

Here is an article that involves disassemble of a Ranger SJB: https://www.therangerstation.com/tec...horn_mod.shtml

Not related to your issue just a visual reference

Yes, when you unplugged the connector that was feeding 12v to SJB from the engine fuse box you would lose the draw from f11
SJB is powered by engine bay fuses 1, 3 and 5 full time, so if you pulled one of those the draw should also go away, in my drawing Fuse 5 powers f11 in SJB
The SJB also get more power from ignition switch when its turned on


Not sure the 'low current board' is a serviceable part so you may be looking at replacing it with a new/used SJB

 

Thanks for the information.