Battery goes dead, no obvious reason.

[DeltaV]

Pull it into the garage/barn at night and shut off everything, let your eyes adjust to the darkness for 5 minutes, and look around for a dull glow coming from taillights, marker lights, license plate light, or dash lights.

Edit: or dome light if the truck has one

Be careful to not step on any mice.
@Kern Dog

 

[zyzzyx]

I agree with some of the prior posts, check the draw with a self ranging digital volt/amp meter. I just had to
replace an alternator on my Sequoia because of a bad diode. Older vehicles should not have any current draw
at all. Put the meter on and start pulling fuses, but first check the alternator! Good Luck.

 

[Dennis H]

Cut out switch has never failed. Easy.

 

[chescharger]

Shouldn't the neg. cable be the one to disconnect for storage?

 

[toolmanmike]

Making it work and diagnosing and repairing the draw are 2 different things.

 

[Mackman]

Maybe don’t leave it inside unattended.

 

[QuickBpBp]

I had this situation with our boat. Turns out it was the radio it was always on with a pinkish light. It was wired that way from the guy before me… I never used it as I have SiriusXM and used a Bluetooth speaker…But it would drain a deep cycle battery in a little over a week.

 

[hunt2elk]

Shouldn't the neg. cable be the one to disconnect for storage?

Yes, and that what Dennis is showing.

 

[Don Frelier]

Yes, and that what Dennis is showing.

Are you "positive"?

 

[hunt2elk]

Are you "positive"?

Guess I'm not "positive" because it is not my car, but all my battery negative posts are at the front of the engine bay.

 

[padam]

If you disconnect the ground cable at the battery and slowly touch the terminal to the battery-does a small spark occur? If so start pulling fuses, one at a time, and test for spark each time. If/when the spark stops occurring you have found the problem circuit. Now you can narrow down the culprit. There is also the possibility you have another poor battery.
Mike

Or put a test light in line, pull fuses til the lights go out. That’s your drawing circuit.
I have a little directional do-hicky that you hold over the wires and it tells you which direction the draw is. I’ve only used it once or twice but it does work.

 

[RemCharger]

In addition to what Mike suggested, even if you disconnect the pos terminal, any battery will self-discharge from non-use. Some faster than others, such as a lead-acid. What battery are you using?

While this has to true over a very long period of time, my example Is parking my 64 in Sept after a season of racing with the battery connected and sitting through -40 till April. And simply firing it up like it was parked yesterday.
A good battery with zero draw will not lose power for a looong time.

 

[rickseeman]

Google

Parasitic battery drain​

It's not a hard test and that's how you fix the problem. You will feel like Einstein when you get done. On my tractor it ending up being the radio.

​

 

[turbine68rt]

While this has to true over a very long period of time, my example Is parking my 64 in Sept after a season of racing with the battery connected and sitting through -40 till April. And simply firing it up like it was parked yesterday.
A good battery with zero draw will not lose power for a looong time.

A flooded car battery will lose about 1% per day at room temperature from non use. More so at higher temperatures. He never answered what type of battery he's using.

 

[padam]

I was hunting a draw on one of my kids cars.

Turned out to be the right side door switch was showing door open, and the indicator on the dash (not dome light) was running the battery down over a week or two.

 

[RemCharger]

A flooded car battery will lose about 1% per day at room temperature from non use. More so at higher temperatures. He never answered what type of battery he's using.

Interesting about the temperature.
My proven testing has all been with lead acid.

 

[Photon440]

A flooded car battery will lose about 1% per day at room temperature from non use. More so at higher temperatures. He never answered what type of battery he's using.

That is high. A good battery should lose only 3-5% per month. It's true about higher temperatures, the ideal is 50°F. Higher than that means more chemical activity

 

[Kern Dog]

In addition to what Mike suggested, even if you disconnect the pos terminal, any battery will self-discharge from non-use. Some faster than others, such as a lead-acid. What battery are you using?

The batteries I've used are all NAPA auto parts brand. They can sit for 2-3 months or more if disconnected and still be good enough to crank this over if they are disconnected.

Does the horn work?
The steering wheel horn pad on that era had foam beneath the contact area for the horn button.
When the foam breaks down the relay is active all the time.
It's a possibility.

The horn has never worked. The prior owner put in a doorbell switch and an aftermarket horn.

Is there an aftermarket radio? Most all the aftermarket will have a memory draw. Those old trucks did not have any draw unless there was something on. Most common was the dome light and if that is going off by the jamb switches properly you should be OK. I can not remember if they had any key lights?

I put in a radio, it is as basic as they came...analog face, cassette. The dome light shuts off as I close the doors. There seems to be no rodent damage anywhere. The starter is a rebuilt mini spec'd for a 1995 Dodge truck and it spins fast. I did the ammeter bypass a couple of years back and installed a voltmeter. It has no light on it but is directly wired into constant power and gives a reading all the time. Could a cheap gauge draw enough juice to drain a battery?
I have no problem replacing the alternator if it is the problem. I'd just want to learn from this to have more knowledge about it.
I've tried tapping the battery cable to the post and see no sparks.

 

[turbine68rt]

That is high. A good battery should lose only 3-5% per month. It's true about higher temperatures, the ideal is 50°F. Higher than that means more chemical activity

New Castle Battery made sure customers were aware of the discharge rate with the flooded batteries before the repros went to tandem gels. My current group 27 gel is 17+ years old. Best battery I've ever owned.

 

[RemCharger]

The batteries I've used are all NAPA auto parts brand. They can sit for 2-3 months or more if disconnected and still be good enough to crank this over if they are disconnected.



The horn has never worked. The prior owner put in a doorbell switch and an aftermarket horn.



I put in a radio, it is as basic as they came...analog face, cassette. The dome light shuts off as I close the doors. There seems to be no rodent damage anywhere. The starter is a rebuilt mini spec'd for a 1995 Dodge truck and it spins fast. I did the ammeter bypass a couple of years back and installed a voltmeter. It has no light on it but is directly wired into constant power and gives a reading all the time. Could a cheap gauge draw enough juice to drain a battery?
I have no problem replacing the alternator if it is the problem. I'd just want to learn from this to have more knowledge about it.
I've tried tapping the battery cable to the post and see no sparks.

Disconnect the gauge.