Help! Battery Dies

[My81Vet]

My 81 Vet dies if it sits for a few days, I have check the most practicle things to see what is draining the battery, to no luck, if you have any ideas that would be great.

Also I thinking if buying a kill switch to attach to the battery can anyone suggest which one I should buy.

 

[73shark]

First have you verified that the battery is good? A fully charged battery should be able to power the headlites for one minute and then easily start the engine. Or you can go to most auto parts store who will check battery and alternator.

If that's OK, then you need to measure the current draw on the battery w/ everything off including courtesy lites. While monitoring current draw, remove one fuse at a time 'til you see it drop which will indicate which circuit(s) are drawing current. From there it's a matter of tracing it down.

 

[6880 Mike]

FWIW: Do you have a vanity mirror? We had a constant slow drain on my fiancee's '96 which we couldn't find. After dark one evening I happened to notice a faint glow around the mirror door. Sure enough, the mirror light was on.

Won't hurt to check.

 

[damoroso]

If the battery and the charging system is working correctly, and there aren't any lights (like the vanity mirror) that stay on, then it's likely the courtesy light timer. It's a small orange box behind the glove box (taket the glove box out, don't try the circus trick of getting under it and reaching for it!). I nearly pulled my entire dash apart looking for a short and it was the timer all along. If I could find someone who can translate the parts on the oringal circuit board to the corresponding new parts, I could rebuild these things for about $15.00 apiece. As it is now, you can jump it and the courtesy lights will work without the delay, or pay about $80 for a replacement part.

 

[Mr. Chuck]

My 81 Vet dies if it sits for a few days, I have check the most practicle things to see what is draining the battery, to no luck, if you have any ideas that would be great.

Also I thinking if buying a kill switch to attach to the battery can anyone suggest which one I should buy.

Visual inspection is an easy first step, with a fully charged battery; check the following (best in a dark space):
1. Spare tire light (located in the rear, area next to the spare) after exiting & closing all doors, it should go out after a nimute or so. If light stays on, then the timer is suspect.
2. Do the same check of the glove compartment light, if door switch isn't adjusted correctley, causing the light to stay on. Checking in a darken garage, shouldn't show any light around the edge of the vanity door.
3. The vanity light again is easier to spot in the dark if it isn't going off when it is closed. If it is staying check the adjustment of the glove box hinges / latching plate is insuring full cover closure (none or very little gap along the top edge of the door is normal).

Assuming you have a volt meter, & battery is near full charge, do these basic electrical test (with engine off):
1. With one battery cable disconnected check and record battery voltage, typical voltage is ~2V / cell (~11 - 12V), depending on the age of the battery.
2. Reconnect the battery cable, measure & record the battery voltage, accross the same points as in step #1, if there is a significent difference / drop in the voltage readings; one two causes are likely. The battery if quite old, may no longer have enough capacity or there exist a major electrical drain (short or mal-functioning timer). Also note that some normal electrical load maybe present, like under hood light if open, electrical clock, dome lights if one more door are open.
3. The above checks should be done with ignition key off
4. Check to insure the rear window defroster switch is off and the indicator switch light is off.

Start engine;
1. Measure voltage from the alternator "red" large terminal (on rear of alternator) to good, clean ground point. A good alternator output should be ~14DC (solid / stable) volts.
2. Verify all wires connected on rear of alternator are tight, clean, no dis-coloration, no signs of over heating, burnt insulation, broken or loose strains at terminals that could short out against car frame or are multipule wire strands are broken at the terminal barrel reducing the ability to keep the battery charged.

 

[Rmodeler]

I had the same problem with my 82. Then I started getting this "rotten egg" smell in car. I didn't put 2&2 together at first. I happened to check the battery when I got back from driving it and discovered the battery was so hot that it burnt my hand! Had it checked out and replaced it. The battery was bulging on the side. Can you say "fire". I was lucky!

 

[Rodney Gold]

A cut off switch is the easiest solution , I have one in my battery compartment. Acts as a theft detterent too as wall as a safety switch if you happen to develop a short or an electrical fire , also makes it easy to work on wiring/electrics as you dont have the schlep of physically havivng to disconnect bat cables when doing so.
Car bats also dont respond well to deep cycle charging , IE continually running flat and being recharched. A good battery will have in excess of a 300 day shelf life if charged and disconnected.