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Mystery battery drain -

829 Views 4 Replies 3 Participants Last post by  WiiMaster
So the girls going over 3 batteries swap in 2 months: something definitely wrong.

The thing we checked: all interior lights are off, and all headlights are off.
Thing possibly wrong: AC relay ( manually turn off both front/rear AC)
  • Things that newly installed since 2022: towing wiring hardness (w/relay) from etrailer.
  • Thing that add-on since 2014 : side step with lighting. I think the electrical goes under the passenger side.

So the routine is voltage measurement (engine off =12.x ) and engine on ( 13-14.x V)=> alternator is charging !

Then connect the DMM inline, power everything off and start check for mA drain ( anything over 25mA) .

I will need to print out fuse boxes and relay diagram to start to pull out the suspected drain .

Is there a common source for the tow wiring hardness elimination?

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I try the easy way, nearly all fuses/front and inside pass/driver side !!! no lucks :mad:

Inline showed 110mA - 130mA drain after 10 minutes of engine off .

I take everything out of radio ( no CD), and remove the fuse from the tow wiring hardness add-on from e-Trailer .

Now: measure the battery: 12.56V. I will take it daily until I get it to drop.
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