battery drain...

[Boss302 22]

i did a search couldnt find anything..

 

ive checked my battery, its fine...take off the neg wire while running, car still runs...

 

 

but every couple days, or sometimes weeks, ill get in, and shes dead :(

i charge her up and shes purring again..

 

i asked a local friend, he said brake/tail light switch were a common problem on them..

 

But wouldnt my tail lights stay on, or light glow...

 

just where is this switch, if it is that...

thanks,.

[shelbyshelby 52]

i did a search couldnt find anything..

 

ive checked my battery, its fine...take off the neg wire while running, car still runs...

 

 

but every couple days, or sometimes weeks, ill get in, and shes dead :(

i charge her up and shes purring again..

 

i asked a local friend, he said brake/tail light switch were a common problem on them..

 

But wouldnt my tail lights stay on, or light glow...

 

just where is this switch, if it is that...

thanks,.

 

I always use the test light method to diagnose battery drain problems. Pull a battery cable off, either one. Use a test light that has a light bulb, not the LED type. Place the ground from the test light onto the battery cable, then using a pair of vise grips or hose clamp, or similar contraption to hold the test probe to the battery terminal. If you have battery drain, the test light will be brightly lit. You can then start unplugging components or fuses until the light dims or goes out, you have the problem. I have found many of these issues to be caused by properly charging alternators or voltage regulators staying turned on after the key has been turned off. Hope this helps.

[Phils69 27]

I did exactly what Shelby said. If light is lit pull fuses one at a time to see which one is the culprit and back track from there.

[69gmachine 15]

You can do the same thing with a voltmeter and all you have to do is touch the leads to the cable and the battery post. Although it will work on either terminal, you should always use the negative side so you don't generate a spark.

 

You can't always count on the problem being isloated to a circuit with a fuse. I just went through this on my main under dash harness. Even after removing all the fuses and disconnecting every single sub-system and harness I still had a short. I ended up replacing the main underdash harness. The short is finally gone, now I just need to put it all back together.

[MustangChuck 16]

I had the same problem. My "solution" was to add a quick disconnect to the battery cables. When I would be away from the car for a while (say, parked it overnight), I would unplug the cables. Since nothing in my car needed constant memory (such as the radio), this worked perfectly.

 

M/C

[danno 128]

Boss, the switch your friend is talking about it the light switch. The reason maybe he mentioned it is because it is easy to leave teh interior light on if the knob is rotated all the way. You might not realize this if one bulb is broke or you only drive during the day. Other than human mistakes, there is nothing about the switch itself that could drain the battery.

[BuckeyeDemon 211]

i don't know if it's a good idea to disconnect the battery while running. it probably acts like a big capacitor to damp noise. however, i've never put a scope on it to really see what kind of noise would be there....

 

hook up a DMM with an ammeter to the battery terminal to measure the current with the key off. it should be really low. open and close the doors to see the impact.

 

you could then start popping fuses to see what circuits the current is going to that's causing the drain. there could also be something in the voltage regulator (i don't know what the circuit is so i couldn't rule that out).

 

if you don't have an ammeter, pick up a 1 ohm or 0.5 ohm power resistor (or something similar) and use your voltmeter to determine the current.

 

without a measurement you're walking blind.