Parasitic draw

Discussion in 'Interior/Electronics' started by Perkolator, Mar 23, 2016.

  1. Perkolator

    Perkolator Veteran

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    Any of you guys had a parasitic draw on your pre-78 Hilux?
    I thought mine was the original alternator, but apparently not. Went to start truck yesterday after being gone for the last 2wks and the battery was completely dead. Damn.

    Gonna charge up the battery and then put a meter on things while I pull individual fuses at the panel. Hoping that will get me close. From there I'll test individual parts hooked to those circuits. Dunno why I didn't do this before and just took the POs word on what he thought it was.

    Does that sound like the correct way to diagnose? Just wondering what the common items are that fail closed and leave a parasitic battery draw. Hoping it's a simple thing, there's barely any electronics in these trucks!
     
  2. Tuhd The Troll

    Tuhd The Troll Veteran

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    As long as your meter can measure amperage, that's not a bad way. First find out total parasitic at battery. If you have about 50-100mA of draw, that's sometimes enough depending on health and strength of battery. A radio is all it takes to drain a battery. The memory circuit that keeps the presets has a tiny draw, but it's still a draw. Start the truck weekly, or disconnect the negative battery terminal when not using it.
     
  3. Perkolator

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    I've only got a crappy Harbor Freight multimeter, hopefully it'll work.
    I'm gonna take the battery in and have it tested, maybe pretend to be the PO with the receipt and have them give me a new one under warranty as it's less than 2yrs old.
    No radio installed on this truck. Everything stock except for some gauges the PO installed.....maybe it's this?
    I'd been disconnecting the battery, but after I did my alt swap I left it hooked up and it still had a draw i guess.
    Just baffled since there's basically zero electronics on this old truck, lol
     
  4. Perkolator

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    Still haven't figured this out. I got a new battery after the last one was drained a few too many times. Still a slight drain of 0.15A. Not effected by pulling any or all my fuses, so it's somewhere else. Tried pulling basically every connection I could find in the engine bay and under the dash, nothing seemed to knock down the draw. I need to look at a wiring diagram I guess. Dunno the names of wires, but the battery has a small pair of wires off positive battery terminal in addition to thicker starter and my alt wires. This small pair has a bad connector in it before going into the wiring harness and when I disconnect it, the draw goes away. I think basically everything goes off those wires.
     

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