Hi, I have a 1994 3.0 4x4 supercab.

Last week I went to start the truck after it had been sitting for a few weeks and it would not start. I took the 7 month old battery back and they charged/ tested it and said it was a good battery and after I installed it back in truck, the truck started up fine.

Today I get in my truck after it was sitting for a few days, and my clock and radio preset stations were reset again, but truck started fine
I checked the voltage of the battery with truck off and it read 9.6 volts.....low!!!!

Any idea what could be slowly draining my battery......all lights and accesories are off and battery cable connections look pretty good.

Could a bad alternator cause this?

 

Either check for current flow with an amp clamp or lift the cable and see if there is a spark.
If there is a spark then something is draining juice.

You need to check each component one at a time, disconnect the component, check the battery.

 

Pardon me, I am not very mechanically inclines here....amp clamp? lift which cable?
Disconnect which components?

 

Does the dome light come on when you open the door ?
Does the dome light go off when you close the door (every time) ?
That damn little light WILL run a battery down.

 

yes, the dome light comes on everytime i open the door, and goes off every time i do close the door.

 

The PCM will have a parasitic drain on the battery , but it is small. Just enough to maintain the engine parameters.
Either the battery is junk , even though it "Tested" OK , or something is draining it.
I mentioned the dome light as I've had that before. Another could be the glovebox or underhood lights staying on.
Have you added any electronics (radio , amp,ect.) that could be left on without you noticing ?

Something to note:
I have a 93 Dodge ram I bought new in Oct. 92. It has 67K on it now. Sometimes it sits for months before I start it.
The original battery lasted 13 years.
The replacement (Wallyworld Everlast , go ahead and kick me) has lasted......


3.5 years

You may think the battery is good , but it may be junk.

 

An Amp Clamp is a meter that attaches around a wire or cable and senses the amount of current that is going through a line.
If you were to put an Amp Clamp on the battery cable and there was an electrical draw on the system then it would show up.
This tool us not something everyone would have so you most likely would need to borrow one.

Lift the battery cable, if there is current flowing in the system you can tell by the spark when you remove/lift the cable.

That is the million dollar question… start with as stated anything new you may have added, any large current draw components, then work to smaller add ons.

Sorry for being vague but quick answers are easier.

Also, the dome light thing is a good one, double check by just closing the door normally, not harder than normal and see if the interior light/door chime goes off.

 

A test light is much cheaper than an inductive amp meter.
To check for current drain on the battery. remove the negative battery cable, and connect the test light between the negative battery terminal, and the negative battery cable. If there is a significant current, the test light will be BRIGHT. Start removing fuses (then put them back if no change to the test light brightness) until the test light brightness decreases. Yes, a bad diode (or voltage regulator) in the alternator will cause a current drain on the battery.

Good luck!

 

thanks all, i cleaned the terminls and cables the other day and everything seems better now.