Finding a short?

[DFrank]

On my '05, the battery was dying if I left it alone for a couple weeks. Then it became quicker. A local mechanic found no short or draw on the battery.

It got to where it would only last a few days, and I replaced the batteries.

The problem was not corrected.

The (brand new) batteries die if left for more than a couple days.

I've taken to keeping a tender on the batteries when I can, but I've killed them 3-4 times in the month I've had them, which I know is not good for them.

How do I track down the short or drain n the battery?

I have a multi meter, and I thought I could set it to read amps, and put it across a fuse location to see if there was a drain on that circuit. Maybe I'm setting it wrong, but I put it on a circuit that I know should show a load, like fog lights when turned on, and I cant find any setting on the meter that reads anything for this condition.

How do I find the draw?

I need to do the same thing on my truck camper, though this is unrelated, as I have it isolated from the truck.

Also, I cant seem to get the charger on the camper to charge the truck. If I take a jumper wire to trip the isolator closed, while using the 120V charger on the camper, the volts don't seem to make it to the engine batteries. This seems like it should work, but it doesn't. I'll read high 13 volts when the camper is charging, but when I close the isolator, the volts still don't seem to read on the engine batteries.

Thanks,

 

[Bob4x4]

http://www.popularmechanics.com/cars/technology/how-to/a5859/how-to-stop-car-battery-drains/

Google is your friend

 

[BigPapa]

What does your volt meter read?

 

[Prairie Dog]

Do you have an aftermarket amp? Sometimes they start failing to turn off.

 

[DFrank]

Thanks Bob. Good read. *This technique should
Help me track it down.*

No amp, aside from factory stereo.*

 

[DFrank]

So I finally tried to track this down again with no luck.

I ground out the lead on al the terminals, so they all bolt up tight again.

I am using my multi meter, set to DC OHMS, and get no reading across the removed negative cable to the battery negative post. I tried moving the selector to different settings and moved the positive lead to each of the three different spots to plug it in. Still no reading.

I've been keeping a genius battery charger on it to keep it topped off, but it still only reads 11.9 volts, when its full. Have I trashed these new batteries already? My '03 only reads 11.9 and it has no issues,but maybe they're on their last legs as well.

Do I need to unhook the other battery to isolate the load to the drivers side battery to test?

Can anyone suggest an easy way to verify that my multi meter actually works? IT will read volts just fine.

 

[Bob4x4]

You need to use the amp scale,start with the highest number and turn it down once you see the number read is less than the max on the scale.

 

[DFrank]

Thanks Bob. I tried this, with the meter inline with the removed drivers negative terminal. No reading. Do I need to disconnect the other negative battery? Should I
Be doing this inline onnthe positive side?

 

[K5IP]

The negative side is the safest place to measure the current, but you must disconnect the negative lead on the other battery too. Leave it open while you are measuring. Make sure you are on your meters amp's mode. Ohms is for measuring resistance, not current.
Rog

 

[SnoKing]

OR, you can try connecting a number 97 bulb between the neg lead and the battery post. Start pulling fuses until the light goes out or greatly dims. SNOKING

 

[DFrank]

So my fuse was bad in the meter. I was able to replace it and get the readings I was looking for. Original draw was reading 2.4 amps!

I didn't really figure out what all was causing this big reading. The last fuse I pulled was carrying the load. It was the radio cluster and the hood lamp. I pulled that fuse and it dropped to .11 amps. Is this low enough, or should it read even lower?

I pushed the fuse back in, and the load was no longer 2+, but just over 1 amp. I pulled the lamp out of the system, and it dropped down to .11. I can't even find the switch that is supposed to turn the hood light off, but removing it is pretty acceptable at this point.

Where is this switch?

What are other people reading for volts on their trucks at rest? Mine only reads 12.4 volts now, which still seems low. It was reading 11.9 with the hood light and possibly the dome lights on.

Hopefully this clears up my issue.

Thanks,

 

[SnoKing]

So my fuse was bad in the meter. I was able to replace it and get the readings I was looking for. Original draw was reading 2.4 amps!

I didn't really figure out what all was causing this big reading. The last fuse I pulled was carrying the load. It was the radio cluster and the hood lamp. I pulled that fuse and it dropped to .11 amps. Is this low enough, or should it read even lower?

I pushed the fuse back in, and the load was no longer 2+, but just over 1 amp. I pulled the lamp out of the system, and it dropped down to .11. I can't even find the switch that is supposed to turn the hood light off, but removing it is pretty acceptable at this point.

Where is this switch?

What are other people reading for volts on their trucks at rest? Mine only reads 12.4 volts now, which still seems low. It was reading 11.9 with the hood light and possibly the dome lights on.

Hopefully this clears up my issue.

Thanks,

I was going to tell you to check the meter fuse and forgot! The hood light most likely has a mercury switch based on angle of the hood. 110 ma's is not bad. I fully charge battery should read about 12.6 v after sitting at rest after 24 hours with "NO" load(think disconnected from the 110 ma static draw). SNOKING

 

[DFrank]

Mercury switch makes sense. The bulb is not well secured and might hang funny and not shut off always. Light is gone, and may never come back.

 

[PBJ2500CTD]

Most under hood lights are now activated by a rolling ball instead of mercury. The ball sometimes sticks in its tube and leaves the light on; especially if the light isn't secured to the hood very well, or if the mechanism is bent to where the ball rolls to the contact end of the tube. New lights can be found on eBay and Amazon for a fairly decent price.

 

[BigPapa]

Glad you found your issue. Here's an unrelated story I thought you fellows might enjoy.

Had a friend that was trying to diag an alternator issue. I told him how to hook up a couple of jumpers between the alternator and the battery to "force" the alternator to charge. He couldn't get it to work and what he was telling me didn't make since so I went over to check it out. He had one short jumper and one long and he had removed the passenger side battery several years ago. So since both jumpers wouldn't reach the driver side battery he had the positive jumper connected to the truck's battery but the negative jumper connected to the negative post on another battery that wasn't connected to anything. Said he didn't understand why that wouldn't work........