Parasitic draw, calling all electrical gurus
 

Hey guys, I've recently run into the issue of parasitic draw. If the Jeep sits for 3 days, the battery needs a jump. I bought a brand new battery back in September, so I ruled that out of the equation. Ended up using my voltmeter to test the draw. Started off by pulling the winch, lights, cb, and lockers: no change. Proceeded to start pulling fuses. Looks like fuse M13 is drawing power even after the Jeep shuts off/all the computers shut off. I'm drawing 1.5 amps initially, which then falls to and steadies at 0.68 after a few seconds. This is still much higher than the 0.05 that I should be at. Looking at the wiring diagram for M13, I'm seeing that it supplies power to the following:
-Siren
-Left multifunction switch
-Remote entry
-Cluster (one of two fuses, not the only one)

Better diagram:
https://cimg6.ibsrv.net/gimg/www.jk-...aa97b7cb6e.png
So now that I have it narrowed down, I have no idea how to proceed. Has anyone on this forum had issues with parasitic draw related to fuse M13? I've been pulling the fuse when parking the Jeep recently, but I'd like to solve this issue before I go on a wheeling trip in August. How would I go about narrowing down which circuit is causing the draw?

How long after you have powered off the Jeep, remote locked it, etc., before checking the current? Also, what method did you use to check current on that fuse? E.g. did you measure voltage drop across the fuse and then cross-reference the fuse manufacturer's data for drop vs current, or use some other method?

I'd wait at least 5 mins before checking current; this allows devices to discharge, electronics to enter their sleep cycles, etc.

I waited 15-30 minutes after I powered the Jeep off before conducting any tests. I should clarify: I powered the Jeep down, locked it, and removed the negative battery terminal. Let it sit for 15-30 minutes, then put my voltmeter in series/between the terminal and battery cable and tested the amperage. Initial draw was 1.5-1.6 amps, but after a few seconds it settled down to .5-.6 amps (I'm guessing connecting the voltmeter "woke" everything up for a second, which would explain why it dropped to .5ish range).

Yes, it woke things up again, and restarted the normal time it takes for things to go back to sleep. That can take up to 10 minutes.
So, after connecting the amp meter in series, you have to wait the ten minutes while ensuring you maintain continuity. Otherwise, every time you lose and reestablish continuity, the time starts over.

I'd disconnect stuff downstream of M13 with the ammeter connected to the battery, after waiting about 10 minutes with the ammeter connected. Start with whatever is the most convenient connector, and is most likely to succeed -- The alarm system/siren would be my first choice.

:beer:

parasitic draws can be any number of things. I have seen alternators cause them as well as electronic componets. Before shooting the parts cannon at it go through and check componets. If your alternator is drawing the the juice it will be warm/hot to the touch when the Jeep is not running. Then take a test light and start checking circuits. YouTube is a great resource. One channel I like is SouthMain Auto.