Something "wakes up" and draws current in the night.


RonD

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It is an HEC dash so needs some power full time to hold memory

It is wakeing up from either an internal issue or external sensor

The 4 door sensors, are activated from a Ground being seen at the SJB or HEC
You said just tossing in you tools causes something to happen, like what?

The door switches on Rangers are a well known issue, so maybe a door switch or its wire is grounding out just briefly now and then, not enough to keep door ajar light on but enough to wake up HEC at different times overnight
 


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Dirtman

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When i mentioned it "woke up" because I threw tools in I ment because I opened the door. Opening the door definitely sets it off but it "should" go back to sleep after a minute. I noticed it also wakes up if you turn the headlights on, turn the dome light on, or hit the brake pedal.

my dome doesnt ever stay on when it shouldn't but checking the door switches seems like a good next step to explore. They are of course a pain in the ass to get to since they are attached to the latch inside the door not the old school buttons on the door jam. Ill go pull them out and test them.
 

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What I was thinking was to pull Fuse #11 in the SJB, that should disable the door open sensing, so eliminate all the door switches as the "wake up call", so take it off the table.

With fuse 11 out I would expect the door open dome light to not work, just as confirmation it is disabled

BUT..................driver door switch shows direct connection to HEC, pin 2 purple/orange wire, so if you were going to test a switch that would be the only one that "looks like" it could "wake up" the HEC
 

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Dirtman

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I decided to do a little experiment last night. I took a crappy HF DMM (didnt want to risk burning up a good one) and left it connected all night reading current through fuse #33, then hooked one of my wifi cams onto the DMM. So throughout the night I watched and recorded it from my phone just to see if the current draw woke up. Anytime the wind blew hard the cluster woke up. It never stuck on (that i saw anyway) but obviously something is loose enough to be shorted by a gust of wind.

So i have confirmation in that respect. Tomorrow im gonna do the same test but just shake the truck with and without fuse #11 and see what happens. That should confirm that circuit is the wake up problem.
 

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Ok no one insult me... I'm writing this only in case someone else googles and has similar issues.

I found the problem. The smart junction box aparently "wakes up" with any change in voltage. I.e if you open a door the system comes alive. Well...

My battery is just dead enough to randomly drop voltage enough to keep kicking the junction box on. I tested it with the old fashion "toaster" load tester and it said it's ok. I took it to autozone and advance and used their fancy electronic battery scanners and both said my battery is bad. Its obviously got enough juice to start up on a full charge but as the charge starts dying it kicks on the sjb and drains it faster and faster.

Solution... new battery. I ended up getting the battery half off after bitching a bunch that the battery is not that old but it was technically out of warranty. I said I'll pay more for the "gold or platinum" series which literally just have a better warranty but they dont sell them in a 59 series.

So I learned the old fashion load testers are absolutely worthless on modern starting/charging systems and to stop over thinking things and double check the simplest solution.
 

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Well, I've certainly been there before - glad you figured it out!
 

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Thanks for posting the solution. That one could easily kick a lot of butts.
 

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Damn do i feel stupid though...
 


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