Help finding a short, Who's good at ELECTRICAL???

[gmbellew]

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[SquareRoot]

Pull a different fuse every night. When it stops draining the battery you found the circuit. That will narrow it down quickly. I have a solution but I'm probably getting ahead of myself.

 

[fast 99]

Should show something? It's late, tomorrow will check a couple vehicles like you have that hooked up.

Using a shunt many vehicles will show a small MA draw. Without it should show a large one...... provided the draw is still present.

Will get back in the morning.

 

[Nasty-LSX]

Should show something? It's late, tomorrow will check a couple vehicles like you have that hooked up.

Using a shunt many vehicles will show a small MA draw. Without it should show a large one...... provided the draw is still present.

Will get back in the morning.

Thanks. What is a SHUNT? Something I can Buy?

 

[Nasty-LSX]

I have a solution but I'm probably getting ahead of myself.

Please tell or PM me. I am tired of this and would like to figure this out. Electrical is my weak side. Very weak!

 

[Grit dog]

Thanks. What is a SHUNT? Something I can Buy?

It’s basically a permanent installation of what you’re doing but it goes on the positive side. (I think). It’s used to measure current draw. Common homeowner application would be in a camper so you can see what components use how much current draw. Like to calculate how long your batteries will last. A shunt I’m sure can measure small currents but it’s typically used for larger currents, but you can buy/size them for whatever. I could be wrong in my understanding but I don’t understand what the advantage would be for diagnosing a problem other than having a constantly visible readout until you fix the problem.
@fast 99, I’m learning here, what would be the advantage of installing a shunt to diagnose a presumably single issue like this?

 

[Grit dog]

Ok, I get 0.00 still. I'm guessing this is going to be something I need to leave to experts. I know online help is really hard when
the people that are helping cant see whats in front of them. Im gonna try a different multimeter with the 10A setting and see if
I can get a draw.

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Ok that’s perplexing! You’re doing it right.
Before I replied earlier I went out and checked the 86 that I knew has a parasitic draw. Digital multimeter like yours but much older. That’s how I knew I had a 40mA draw like I said. lol.
Just to make sure I wasn’t giving bad direction..lol. I’m no expert either.
I might suggest reading the manual for your multimeter? Does the “range” button do anything? You should not see 0’s if you know you have a draw.
Also test what it shows if you create a draw (a small one, like the dome light, something that draws less than 10A).

Side question, you said that battery is only 4 months old. Why does it look kinda crusty around the caps like it’s off gassing or leaking around the caps? Maybe it’s just the photos but I wouldn’t expect any gunk around the caps where you add water.

 

[Grit dog]

K so I was intrigued and looked up the owners manual for that meter and looks like you’re doing everything right, now.
You set volts to DC default is AC.
You’re on auto ranging. Note the cutoff between mA setting and A setting is .4A or 400mA. It’s possible the 10A plug was/is where you need to be if you have larger draw.
You’re on auto setting which auto ranges the sensing.
The instructions did say supposed to disconnect the power source, then hook it up then reconnect power. (+ side of battery in your case)
Idk if that will make a difference. Easy to try.
Last thing I can think is did you blow either of the fuses and is that making the meter not read?
Good luck!

 

[Radiohead]

Unplug the two wire connection on the alternator with everything else as normal and see if the draw goes away.

 

[Hunter79764]

My thoughts went to the alternator as well, try disconnecting it and see if you have an issue that night.
I also wonder if your multimeter fuse could be blown? With it connected on the 10A scale and connected the way you showed, open a door and see what you read. It should give a noticeable reading. If the dome light doesn't work and the meter still shows 0.00 A, your meter fuse is blown I think.

 

[fast 99]

@fast 99, I’m learning here, what would be the advantage of installing a shunt to diagnose a presumably single issue like this?

Can monitor electric flow while turning items on and off. A MM on amps works similar except you're not limited to 10 amps or whatever the internal fuse is.

Although it probably doesn't apply here, later model vehicles have draws until the systems go to sleep. Some of those have rather high current flow. I got tired of buying $10 fast blow fuses forgetting the meter was set on amps.

Vehicle tested does not have a draw. First picture shows 3.77 amps through the meter with park lamps turned on. Second is the same draw using a shunt, shows 4.0 on MA scale. Third, lights turned off through a shunt, O MA scale. Has same 0 reading without shunt using amps through meter.

Reason I had to use 2 different meters is the internal fuse is blown on the meter that reads MA. lol

The rule of thumb we use for diagnosing is .05 MV or more using a shunt is a draw. Safer to use the negative side not as shown in the pictures.

Hope this helps.

 

[Don Ainsworth]

My 2 cents. Check automatic choke wiring connection. It may have been accidentally reversed.

 

[Grit dog]

Can monitor electric flow while turning items on and off. A MM on amps works similar except you're not limited to 10 amps or whatever the internal fuse is.

Although it probably doesn't apply here, later model vehicles have draws until the systems go to sleep. Some of those have rather high current flow. I got tired of buying $10 fast blow fuses forgetting the meter was set on amps.

Vehicle tested does not have a draw. First picture shows 3.77 amps through the meter with park lamps turned on. Second is the same draw using a shunt, shows 4.0 on MA scale. Third, lights turned off through a shunt, O MA scale. Has same 0 reading without shunt using amps through meter.

Reason I had to use 2 different meters is the internal fuse is blown on the meter that reads MA. lol

The rule of thumb we use for diagnosing is .05 MV or more using a shunt is a draw. Safer to use the negative side not as shown in the pictures.

Hope this helps.

Yes that makes sense. And a shunt is designed to measure large amp flows.
I was confused as I wouldn’t consider buying one to find a parasitic draw because I’d presume it is not large enough to blow the fuse(s) in a multimeter.

 

[Robert Bare]

I'll throw in a bit-
Some led test lights will not work for such a test.
Battery should be able to handle an overnight drain of several amps and still start vehicle. Get it tested.
Meter may have a blown fuse. Any quality meter has a separate one for amps.
Some items in vehicles don't have a draw until after they have been powered up. So you have to unhook battery, hook up meter,amps, turn on key, turn off. If your meter only does 10A, make sure you don't have a bunch of crap turned on when doing this, -heater, wipers, etc, bot DO turn on radio, especially if aftermarket. This is why mechanics use a battery switch, install it, run vehicle, turn everything on, turn truck off, hook up meter across disconnect switch, open switch. This way everything gets activated.
From there is easy, you will see the draw, then start unplugging fuses, relays, etc.
Most common items-
Aftermarket electronics, especially a radio
Sun visor lamps
Glove box lamps
Kick panel lamps(older squares)
Bad alternator diode
And I could go on--
But, as I said, I suspect 2 issues, slight draw and weak battery.