Parasitic draw
#1
12-01-2014, 06:07 AM
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Parasitic draw
1994 Ranger 3.0. I have measured the draw with ammeter at 3.48 amps. have removed every fuse and relay on both panels with negative results. Have disconnected the A/C clutch leads, the alternator leads, the starter relay, and the solenoid/starter leads with negative results. I have measured the alternator output in both AC and DC scales. DC is good at 14.3 but there is a .011 indication of AC current at battery. Have read that AC current is a sign the diodes are bad but can't find any range of voltage for the problem. Anyone know if .011 AC is enough to trigger this issue? Thanks in advance.
#2
12-01-2014, 09:26 AM
#3
12-01-2014, 03:57 PM
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Thanks Roger, but I've done every fuse and relay I can find twice and the draw still there. I thought the same about having completely disconnected the alternator, just needed some assurances. I did measure as much as 15+ volts coming from alternator with engine running... its a bit high. Could that indicate an issue?
#5
12-01-2014, 11:33 PM
I assume you're talking about AC ripple on top of the 14.3 VDC. I don't have the specs for what's acceptable, but put it in perspective. That's less than 0.07% if it's peak-to-peak. Seems pretty dang clean to me.
#6
12-02-2014, 04:40 AM
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Parasitic draw
I really appreciate the feedback guys. I have measured the same draw (3.48 amps.) with all wires removed from the alternator as well as the starter. The AC voltage was read at the battery with the engine idling. I've even tried finding any component that feels warm. Could I be missing a relay somewhere other than in a fuse panel?
#7
12-02-2014, 07:50 AM
Good trouble shooting & suggestions. Check the brake & back up lamps to see if their respective switches may be stuck closed & the lamps are remaining on.
If you have a tape player, check to make sure a cassette isn't stuck in the eject mode, as it could cause the motor to continue to run.
Will be interesting to hear what you finally find the parasitic drain cause to be.
If you have a tape player, check to make sure a cassette isn't stuck in the eject mode, as it could cause the motor to continue to run.
Will be interesting to hear what you finally find the parasitic drain cause to be.
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#8
12-02-2014, 08:42 AM
Alternators are 3 phase generators you will always see a small AC ripple. The battery acts as a filter to smooth it all out. Take the fuses and relays out and leave them out until the draw goes away. Just keep track of what goes where. Is there any aftermarket stuff on this truck stereo etc etc. I have had those cause this kinda of issue.
#9
12-02-2014, 12:08 PM
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Troubleshooting on hold for a few days since I have to work outside. The weather here has turned wet and colder. So, as soon as things get back to drier and warmer will start checking everything over again. I'll follow your suggestion of leaving the relays and fuses out as I progress. One other point that I didn't mention was that when I disconnect the positive cable at starter relay the draw falls slowly on the meter, its not an immediate drop. Don't know if that could be significant or not. In the meantime I've been disconnecting the negative clamp after parking it, keeping a 1/2" wrench handy. By the way, no aftermarket accessories of any kind.
#10
12-16-2014, 02:11 PM
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Finally some decent weather
Got to test some more today but even more confused. I did as suggested and took each relay and fuse out one at a time, leaving them out as I did the others. I found I could get the the draw to drop to 1.46 amps. but the mystery was that it would drop when I removed either the #2 fuse (fuse panel), #3 fuse (fuse panel), or #4 fuse (EEC) as well as the #16 fuse (air conditioner clutch). If any one of them was plugged back in the draw returned to the 3.46 level. I had already tried unplugged the A/C clutch connectors with no change in the draw. I've never claimed to be a automotive electrical tech but do have some experience tracing these things down... not so in this case.
#11
12-17-2014, 11:58 AM
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Got to test some more today but even more confused. I did as suggested and took each relay and fuse out one at a time, leaving them out as I did the others. I found I could get the the draw to drop to 1.46 amps. but the mystery was that it would drop when I removed all the fuses as well as relays. With all out of the box if I plugged back in the one for the hood lamp or the one for the alternator the draw went back up to 3.4. If I plugged back in either then #2 fuse (fuse panel), #3 fuse (fuse panel), or #4 fuse (EEC) the draw returned to 3.4. When each one of them was plugged back in the draw returned to the 3.46 level. I had already tried unplugged the all the alternator connections and repeated that this time with no change in the draw. I've never claimed to be a automotive electrical tech but do have some experience tracing these things down... not so in this case.
#12
12-17-2014, 06:25 PM
Just thinking about things that could act out & cause parasitic drain, windshield wipers that don't properly stow & turn off, tape player motor stuck on, stuck tape/not fully ejected, cigar lighter, stuck on brake stop lamp switch, under hood or glove box lamps that don't turn off, add on electronics that act out, or aren't turned off, window, or electric seat motors acting out, GEM not timing out & putting things it controls to sleep, dome, or cargo lamps switch turned on, are some things that come to mind.
#13
12-18-2014, 04:28 AM
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parasitic draw
Thanks PawPaw. Unfortunately our weather has turned for the worst so I'm on hold again. Having read some other threads is it possible my truck has other relays besides those in the two fuse boxes? I know its not the starter, alternator, or A/C clutch as I've disconnected them completely yet the draw is still there. I'm okay disconnecting the neg. terminal every time I park it for more than a few hours but its driving me bonkers.
#14
12-18-2014, 04:55 AM
You pulled every fuse, relay, and alt. with your amp meter hooked up does the truck go into sleep mode? There is quite a few direct draw items that you might miss, ABS module, Air bag module, ECU, GEM, can you get the draw down by taking the feed wire to the fuse boxes? I have seen a shorted cell in a battery once, drove me crazy looking for a draw, turned out to be the battery. Keep an open mind, check for coins or gum wrappers in the power outlets, specialy in the back.
#15
12-18-2014, 05:22 AM
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parasitic draw
David 7.3, thanks for the feedback but I have pulled every fuse in both boxes and found that with them all out of the power distribution box the draw drops but if I plug back in any one of the alternator fuse, the #2, #3, or #4 the draw returns. Have not yet tried removing everything in the under dash box at the same time so that's my next move.
The battery is new. Replaced it, maybe unnecessarily, due to this issue. Mine is a '94, no air bags, rear ABS only, can't hear any humming as would be the case if it were an ABS module.
The battery is new. Replaced it, maybe unnecessarily, due to this issue. Mine is a '94, no air bags, rear ABS only, can't hear any humming as would be the case if it were an ABS module.