Hi,

I recently noticed a parasitic draw off with the colder weather. I thought the battery was just toast, but I'm still losing ~4amps with no key.

Testing with the multi-meter off the battery, I've got it figured out to be fuse #10 in the cabin, which says its the Cluster (RUN/START), 4×4 module (RUN/START). I pull it, amps drop.

It also sounds like something in that panel is making noise, like a relay.

Anyone have an idea how to remedy this? New cluster module?

Thanks for any help.

 

A lot of Cabin fuse 10's from 1983 to 2011 Rangers, and 2019 to 2023 Rangers

What Year Ranger?
Also engine model might matter

 

Sorry, I thought the forum listed my truck's details.

2004 Ranger 4.0L XLT

 

No worries

Cab fuse 10 is 10amp for cluster and 4WD module, I assume you have a 2WD?

If 4WD then the noise behind the radio area is the 4WD module, that's where its located and it has 2 relays inside
Article here on getting to that 4x4CM unit: https://www.ranger-forums.com/how-di...lation-140275/

The 2001-2005 4x4CM units did have issues, redesigned for 2006 and up but NOT backwards compatable


Cluster has no relays or anything that should may any noise, and you can not just swap clusters on 2004-2011 Ranger as they were Digital, so to prevent "odometer swapping" the Digital clusters are matched to the computer, so have to be "re-matched' if either needs to be changed

 

It is a 4WD.

The humming is in the cabin fuse panel (passenger side floor,) it stopped when I disconnected the lower wiring harness next to the fuses and connected it back in. Nothing heard behind the radio as you mentioned. It has not started again, so maybe a fluke.

When the #10 fuse is pulled, the 4WD and cluster don't work, as expected.
When the #10 is in, everything is working as expected. Gauges are functioning, and no sporadic jumps or anything. 4WD lights work and you can hear the mechanical parts engaging when switch is turned.

Is it common for a cluster or 4WD module to get cooked and cause a constant draw that anyone knows of? Or is it best to rip out the dash to get to the modules and check for draw on both units?

Thanks

 

No, never read about this specific issue

Have read about 4x4CM failing, but no 4WD shifting not a drain
Never read about 2004 cluster failing although it must happen just not common

Have read about SJB failing, corrosion usually
Haven't come across an SJB schematic in my travels

The fuse 10 red/yellow wire comes from pin 25 on the SJB connector C220B, but its spliced in the dash to go to both Cluster and 4x4CM
And that same connector also has several 12v key on wires so hard to say if drain is in the SJB or the cluster or 4x4CM
You could pull just the radio to access the 4x4CM so you could unplug it and see if drain stopped, then you would be down to SJB or cluster

2004/5 SJB are the same

 

So I did some more digging today, and now have even more unknowns.

I needed to drive the truck the other day, so I made a jumper fuse on/off switch to shut off when not driving. I had that in Cabin Fuse #10 and the battery didn't drain when switch was off - As I planned.
When the truck was on, and I would turn the switch on, I could hear the alternator kick on and seem to be working harder than I remember hearing at idle (and even driving at low speeds,) so I figured I'd just leave the fuse off.
While driving home, the lights started to dim and the radio died, like the alternator wasn't working. The second I turn the fuse back on, everything lit up and worked fine. I'm guessing there must be a link between the alternator and the dash or something allowing the battery to charge.
That was Wednesday night. I shut the fuse off and it sat all day today till I had time to look more.
(The alternator is putting out the 14V+ as usual. I tested that on day 1)

I went out today and check for draw while it was off and sat for 30hrs. Battery was holding 12.4V with the fuse switch off. With the switch on (#10 live) there was NO DRAW. (Typical low 0.2A actual, not the ~4A mentioned the other day)
After starting the truck, then checking again, the draw was back.
I went back to the panel and checked all the fuses (I stupidly stopped the other day when I found #10)
There are three fuses which all cause the 4A draw to drop.

#9 - Cluster air bag indicator
#10 - Cluster (RUN/START), 4×4 module (RUN/START)
#12 - Center console subwoofer amplifier, Satellite radio

I took out the radio and the 4WD module. They are both unplugged. The truck is still pulling the 4A without the radio or 4WD.

Any idea where to go from here? Head to the dash? Does anyone know of anything shared between all three of these fuses?

 

One thing in common, for sure, is the SJB

9 and 10 are key on power only, so pulling out the fuses shouldn't be needed with key off, test if either has 12v with key off, it should not, if so then short inside SJB, OR ignition switch

12 is full time power, so pulling this fuse and seeing a drop, key off, would mean devices on fuse 12 are ON when they should be OFF, if there is still a draw with 12 out then problem inside SJB
No connection to ignition switch

Yes, fuse 10 turns alternator on and off, so no fuse 10 means alternator will not start up with engine, so you would be running off the battery
If you pull out fuse 10 with engine running then alternator would stay running/working, until engine was shut off


Extra credit, lol
Alternators are different than generators, although people often use these words interchangeably
Generators use permanent magnets so can generate electricity just by spinning them, and they won't drain power when not spinning, but also hard to control voltage OUT as it varies with the RPM of the generator, these were not great for cars/trucks, but very good when used to generate electricity from a STEADY RPM source

Alternator's need startup voltage to CREATE a magnetic field(no permanent magnets)
That's where, in this case, fuse 10 comes in, its powers the Battery Light on the dash, and that bulb is connected to the voltage regulator in the alternator
Key on sends 12v to the Battery Light bulb, that 12v passes thru the bulb to the Voltage Regulator, which is at 0volts with engine off, so Battery Light comes on
Voltage regulator sends that 12v to the rotor, also at 0volts, but the 12v causes rotor to become an Electro-Magnet
When engine starts, alternator spins and the rotor's magnetic field starts to generate electricity, once its starts to generate electricity its self sustaining, so Battery Light goes OFF
So unplugging fuse 10 at that time wouldn't matter
Variable RPMs, since the rotor voltage can be adjusted, the OUTPUT voltage can be adjusted, so better for cars/trucks with RPMs between 700 and 4,500
If you were to leave fuse 10 on the non-spinning alternator would drain the battery because its generating a magnetic field around the rotor all the time, for no reason

 

Sorry if this gets posted twice slightly different, my first message disappeared.

Today, I went out, connected the battery and there was no draw. Even after starting and letting things run, no draw after shutting off ignition. Radio and 4WD are still pulled.

I checked running voltage as mentioned:
#9 is pulling 3v with key out.
#10 is pulling 0v with key out
#12 is pulling 11.88v as expected.

Do I pull the ignition switch and check things out or would it be safe to assume my SJB is on its way out since I'm getting such weird, inconsistent results?

 

More likely to be SJB
Ignition switch is just a slider type switch so would tend to be a more repeatable failure mode, but its possible, just less likely

There were only 2 models of SJB, with Keyless entry(Fobs) and without Keyless entry
And no, you can't get the Keyless entry model and add Fobs, more wiring was involved, lol

 

I found a good looking SJB on eBay and finally got it installed. Things seem to be behaving with a constant draw of only ~0.4A with everything plugged in and the keys out. I haven't driven it much, but everything seems to be operating well.

When unplugging the harnesses, it seems like I may have found the culprit. Corrosion on several of the pins and one pin had completely rotted off. I've never noticed a leak on that side and there isn't any sign, but I'll leave the panel cover off and check on it after wet weather.

Thanks for all your help and hope this post helps someone else in the future.