Need help with parasitic draw on my 2005 CRD

[seafish]

Serious question —

I am wondering how you guys check for parasitic draw on the dash end fuse panel without opening the door and setting the interior light on, this creating an instant parasitic draw ??

I am sure that there is a really simple solution that I am totally missing, so please feel free to insult me while you provide the answer.

ALSO, diving further into the problem, it seems like I have a .4 amp ignition off parasitic draw traveling through the ground cable.

And when I remove 2/3 of the 50amp JB Power fuses in the engine fuse box, it drops from .407a to .034a in steps as I remove each 50 amp fuse.

My problem is … I have NO idea what the JB power fuse supplies…again, I am already feeling particularly stupid today having blown the DVM 20 amp fuse once already while putting the battery on the trickle charger for more testing tomorrow, so insults are warranted and welcome.

It is also possible that I am not giving the ECM and modules enough time to got to sleep, which brings me RIGHT back to the first problem of opening the door to check the dash fuses for current drop.

ALL ideas welcome.

 

[seafish]

OK just learned that all 3 "JB power" 50a fuses are the supply circuits for the interior junction box fuses, so still need to know how to check the dash end fuses for draw with the door open!!! Anybody wanna call me stupid by giving the obvious answer that I must be missing??

 

[seafish]

ALSO gonna start looking at the wires in the door loom for a short

 

[KJowner]

Before you get too involved in chasing it try pulling the radio fuse and see if that has any affect.
I'm not sure where the interior light switch is in the door, just looked at mine and it's not obvious, it may well be in the door latch, if so then resetting it with a screwdriver will switch it off.

 

[seafish]

Before you get too involved in chasing it try pulling the radio fuse and see if that has any affect.

Ok Ill try that first.

I'm not sure where the interior light switch is in the door, just looked at mine and it's not obvious, it may well be in the door latch, if so then resetting it with a screwdriver will switch it off.

Mrs. AI Interwebz seems to confirm the existence of a latch switch, so I will try the screwdriver "closing" and see what happens.

God how I often miss the days of simple analog switches as opposed to todays microswitches!!!!

 

[ikuo78]

I think you can find circuits that are consuming power by removing suspect always-on fuses one by one and reading the change in dark current, as you did with the junction box.
If you are concerned about the current value of the interior light, remove the interior light bulb.
If you disconnect the devices on the suspect power supply circuit one after another, you will reach the cause.
If there is a leak from a cable or terminal, I think it would be a good idea to read the current value of those wirings with a loop probe.

 

[seafish]

If you are concerned about the current value of the interior light, remove the interior light bulb.

Yes that is a good idea and is actually my backup plan … but I didn;t want to risk breaking the stupid plastic switch/lenses while trying to take the bulbs out so I will try to close the latch first with a screwdriver.

 

[seafish]

Diagnostic Update —

I charged the Duracell (USA made by East Penn!!!) lead acid battery overnight with the ground wire disconnected, then opened the door and closed the latch with a screwdriver. @KJowner this worked great to keep the interior lights off even after I reconnected the ground wire and negative terminal with the DVM leads with the DVM set to read up to 20A but also kept had the door open so I could access the dash end fuse panel.

Immediately the DVM registered .378 amps and stayed there as I pulled each and every fuse in the interior junction box which zero change in the current flow registering on the DVM until after 10 minutes I saw it drop to .055 and then eventually .034 but with NO change as I pulled each and every fuse UNTIL I also pulled the BCM double fuse when it dropped to 0 and then rose up to .378a when I plugged it back in.

In my mind, this means that the BCM module, or one of the sub modules in the same circuit, is taking longer to go to sleep then it should be (supposed to be closer to 3 minutes). I triple checked this 3 times by removing the BCM fuse and then plugging it back in and each time the current read 0amps then rose to .378 until it dropped to .034 after almost exactly 10 minutes. Though this is inconvenient, but is NOT a major problem as that circuit IS eventually going to sleep and the final .034 amp draw is at the high end of the allowable draw spec, but STILL within specs.


After all of this diagnosis (took about an hour), I checked voltage at the battery and it was 12.69 and then I also put a carbon load tester on the battery. IMPORTANT NOTE: I always load test batteries with the ground terminal disconnected to prevent current spikes that might EASILY **** up one of the modules, or even the ECU right after I determined that they were all pretty much good !!!

Load testing the battery at 400 amps showed the battery still good at 10.5 volts.After load testing the battery recovered to 12.6 volts.


My final conclusion is that likely one of the sub modules within the BCM circuit is taking longer to go to sleep and thus eventually drawing down the battery after not driving for a couple weeks. It is also possible that the battery is on the verge of failing even though it still showed good.

I might cure this inconvenience by either removing the JB fuse that supplies the BCM circuit, or maybe pulling the BCM fuse at the dash fuse box, or maybe adding a ground disconnect switch at the battery, or maybe plugging into a solar or other trickle charger when I am not riding Maya for more then a week. Eventually I will buy a new battery when this one dies completely.