How do I find an amp draw? my batteries dead.

[912504x4]

I had an issue with my A/C condenser leaking 134 so I parked the truck for about a week while I waited for the replacement to arrive.
The condenser came in and I unbolted tha radiator and pulled it out then pulled the condenser out and replaced it. Then I reinstalled the radiator and filled it. When I tried to start it the truck wouldnt even click or anything.
I put the battery charger on there and when I got it running I filled the 134 back up and checked the radiator. The truck was a little low so I turned it off and picked up a gallon of antifreeze the next day to refill it.
The next day after I filled it up I tried to start the truck again and it was dead again.
I have the charger on there again but I am afraid it will leave me stranded somewhere if I shut it off for too long.
Either the truck was having a problem before this and the parking just gave it time to drain or it is somehow related to the work? I dont believe that.

How do I test for a voltage draw with the key off? I am a shadetree king as far as bolting things on and off goes but have no clue about electricity.

Anybody have any tips they care to share?

Thanks, Eric

 

[Roland_Jenkins]

Disconnect the battery ground. Put a multimeter between the cable and the body to see how much of an amperage draw there is. Then start pulling fuses one at a time and checking the amperage draw.

If its a small amperage draw, say 2 amps or so it will often as not turn out to a bad glove box or under the hood light switch or something similar.

 

[Agnem]

Like Roland said, but don't forget to disconnect BOTH grounds, and check the voltages of each battery. If one has shorted cells, it will pull the other one down.

 

[9073]

The test is called a parasitic load test.

It is pretty simple.
1. Place Multimeter in line between battery and ground cable.
2. Read Meter, depending on the vehicle this should be a low number.
3. Find the source either by pulling fuses or disconnecting other sources of possible draw.
4. Eliminate the source of draw.

Matt H

 

[tonkadoctor]

I concur

Get the batteries load tested first to see if one has a bad cell and then test as Roland stated.

 

[sassyrel]

and if those dont cure the problem--after the batts are charged up--disconnect the hot wire off the alt overnight--if the batts are still up in the morning--you have a shorted diode plate in the alt--replace--

 

[912504x4]

tested tonight

I managed to get some quality time with the IDI today and found that if I pull the domelight/glovebox/radio/etc fuse my voltage actually drops. I am not sure if this is because the door is open and the dome light is trying to be on even though juice isnt hot enough or what.
I felt like the batteries needed to be charged up again so I can test accurately while holding the door button in so the dome light doesnt light.

Will post again later, hopefully with load found.

Thank you, Eric

 

[Russ]

Pull the bulb out of the dome light No need to hold button in.

 

[912504x4]

juiced up

I charged the batteries up best I could and tried to retest with the domelight fuse pulled. The batteries are still low but were holding strong for the most part at 10.8 or 10.6 back and forth.
I plan to let it set overnight and retest thursday after work provided I get some time before dark.
If the charge is still holding at 10.7 -10.8 what will I need to look at first. I know the glove box light is not sticking on because I can see it when I lay under the dash and look up.

The dome light seems obvious but I didnt see it on just now.

Thanks, Eric