Battery and Brake light on, Multimeter testing

[BostonGST]

I have a couple of problems. My car dies overnight, i'm guessing from a parasitic drain. However, today, after driving for a little my battery and brake light turned on and stay on. I immediately pulled over and want to figure this out.

I bought a multimeter and tested the battery w/the car off. It read 12.04 I believe. Turned on the car and immediately jumped to somewhere around 15.4. I also moved the black tester from the meter and put it over the battery ground on the chassis and it read the same (this means the ground is okay?). Any ideas what to check/what might be wrong?

Also, last night I pulled the red battery terminal and put a the multimeter inbetween the connection on ohms and it read 7.6, so this definitely means a drain? Pull the fuses one by one?

 

[1990TSIAWDTALON]

With your multi-meter in between the positive terminal on the battery and the positive cable, start pulling fuses until the meter doesn't read any draw anymore then look for something that is staying on on that circuit. 7.6 amps (i assume) is a BIG draw on the battery like a stereo amp, dome lights, brake lights staying on, etc... You are on the right track and asking the right questions. Keep us posted as to which circuit it is on and maybe we can help determine what the draw is. Good Luck!

 

[BostonGST]

Ok thanks, i'll do that after work. Any ideas on the battery and brake light coming on? It usually looks like it's the alternator but mines putting out 15.4, what can I test for the cause of the check lights?

 

[DogWhistle]

Welcome to the forums, Boston. Finish filling out your profile for your car so that we may be more helpful on future questions. Those that check your profile can tell you are a 2G by the model, but having it appear in the threads will reduce bad advice given for the wrong model.

What you are experiencing is a charging system issue. It has happened to many dsmer's before. Check out this thread:

http://www.dsmtuners.com/forums/art...55-alternator-issues-brake-battery-light.html

The Search box will help you answer many of your future questions, since, as I mentioned, most of these things have happened to others.

Best of luck with your ride!

 

[BostonGST]

Hey DogWhistle thanks for the warm welcome. I just updated my year to 97, and did find that post before making my own post. I was confused because my alternator is sending current to the battery. Is 15.4 too high, meaning the regulator is messed up? I've been seeing contradicting info online, some say anything over 14.4ish is bad, others say 15.4 is okay...

Also that post says if battery and brake light are bad then it's the alternator so does that mean it's 100% the alternator and it needs to be replaced?


Thanks for all the help and input!!

 

[Blurred Talon]

Usually when both those lights are lit, your alternator is toast. I've replaced my alternator a couple times in my car (cheap rebuilt junk).

Best thing to do is to remove the alternator and have it tested.

 

[BostonGST]

Okay thanks, I had my mechanic change it a couple weeks ago when it went bad. It should still be under warranty so I'll take it back. I wanted to make sure it was deff the alternator and no other tests I can do myself to check for anything else

 

[1990TSIAWDTALON]

On your battery drain issue, you said you had your multi-meter on OHMS, change it to AMPS (draw) and see if you are getting any battery drain (in amps). If so, then do the fuse pull check until the amp draw is no longer there. If there isn't any or only a small (milliamp) draw then that is just normal and probably pulling a very small amount of juice to keep the clock running and your presets on your radio set. If it is drawing 1 amp or more then I would start looking at larger amp devices (lights, amplifiers, etc) that are still ON when you turn off your car. Thought I needed to clarify what I told you so you could check that.

 

[BostonGST]

yeah i'm pretty sure I had it on ohms. I don't know anything about electrical stuff So set to amps. Disconnect neg terminal, connect multimeter one on battery and other on neg battery terminal. Then if over 1amp I should start pulling fuses to check. For amps side the options are 200m, 2000m, 20, 200, and 600. I'm guessing have it on 20?

 

[Blurred Talon]

Don't disconnect the negative terminal, that can cause damage on newer cars. That check was popular on old cars but on newer computer controlled cars it can cause damage to the electronics.

Google how to check for a draw on a newer car.

 

[1990TSIAWDTALON]

Well I have never had a problem checking draw with a amp meter and these cars are not new (and neither am I), but for peace of mind you might check out this article to help determine your draw. I always checked by pulling the POSITIVE cable off and connecting my AMP meter in between the positive terminal and the cable that I just removed. I always used 20 amp setting on my digital multi-meter. BUT...if you feel you will hurt something then try a different method.

Parasitic Battery Drains - Diagnostic News

I wouldn't want to mess up any electronics but I have done this on my '90. It was the stupid hatch, thought it was closed but the light was still on. Slammed it closed, end of problem.

 

[luv2rallye]

First make sure the alternator fuse is not blown. Then do this test: http://www.dsmtuners.com/forums/new...reeway-electrical-problems.html#post151165661

 

[johneclipse]

Ohms will not show you a draw. It is used to verify continuity between two objects.

Need to set to amps, disconnect your positive cable. Leave the negative cable connected, use "red" multimeter lead on positive battery terminal, use "black" multimeter lead on the disconnected positive battery cable. See what the number is.
As stated, anything above 1 amp or so, I would pull 1 fuse at a time, check the number after EACH fuse has been removed. If number hasn't changed, replace that fuse and pull another. Rinse and repeat until the number changes.

 

[BostonGST]

My meter was being wonky with the readings so I figured i'd take it to my mechanic since everyone was saying alternator and he installed it. It ended up being the fuse was blown and there's to parasitic draws, my batters just leaking.

Thanks everyone for all the help!!!!!

 

[1990TSIAWDTALON]

Thanks for checking back in and letting us all know. We like to help and its nice to know when we got it right. That big fuse blew on me before also, but I have a 90, so all my electric seat belts, headlight doors, dome light, cigarette lighter etc quit working. Mine had a weak little 65 amp stock alternator so I upgraded to a 96 Gallant alternator with 90 amps and I am very happy. Its a straight bolt in swap. Moderators.... I think you can close this one up!

 

[BostonGST]

So yesterday I picked up the car, turned it on everything was good and started driving it, drove like 30 feet and turned on my headlights. Two seconds later the fuse blew and the car died. (The headlight fuse is what blew before)

I got my buddy to drive me to auto zone and replaced my battery because it was deemed bad and bought 2 40AMP fuses for the headlights in case it blew again. I went back to my car and switched the fuse, screwed that little screw in and then connected the battery. Turned on great, headlights on and 2 minutes later POP they go out.

I took the headlight fuse out and switched it with another new 40amp and told myself I wouldn't turn on the headlights until I get it home and figure it out. Well I go to screw in the fuse and see a spark. I take the screw out and go to see if anythings wrong and the cars completely dead, nothing.

In hindsight I should have unplugged the battery before changing the fuse. Any idea what happened? I blew the main fuse and that's it? Or is it something more serious? And seems like there's a short with my headlight fuse. So check every connection with that? The kid I bought it from put in an aftermarket radio and all the radio wires are spliced and put together with electrical tape, could that effect any of this? Radio circuit linked with headlights at all?


Thanks again for all the help

 

[1990TSIAWDTALON]

What fusebox are you working in? Check the 80 or 100 amp fuse that is the alternator fuse. I don't have a 2g so I can't tell where it is located but on the 1g it is under the hood bolted in with 2 #10 screws that you just loosen and then pull the bugger out and slide another in. Definately sounds like a dead short somewhere or you are using a 40 amp when maybe it should be a bigger fuse. Does the panel say that it should be a 40? I sure thought we had you fixed up. Keep up the feedback. The more details the better.
In another thread, a member said he had a loose fuse box and the bottom of it would sometimes ground out and blow fuses. Might want to check that out too. I just remembered reading it not too long ago.

 

[BostonGST]

The fusebox is under the hood and the diagram on the box says 40amps for the headlight fuse. The kid installed some high powered HID lights so maybe he just spliced the wiring together and taped it up like the aftermarket cd player and it's shorting. I talked to my mechanic and he's looking it over, hopefully that's what it is and it's an easy fix.

I'll let you guys know what he says, and thanks i'll look for that post about the fuse box and see if it could be the case

 

[BostonGST]

Got my car back and the wiring for the headlights was all wild with some of it stripped and touching the frame. It's all patched up and headlights work well except my batteries still dying overnight. I unhooked it and left it indoors for a couple day and when I put it back in my car started fine. So there has to be some kind of parasitic draw.

I also found out my multimeter doesn't read AMPS. Everything I read online said to buy a cheap multimeter and I never thought to see if it could do amps. So i am going to go and buy one that can and do the draw test with it. I am very familiar with the fuse box under the hood at this point.

There is another one in the cabin correct? It's under the passenger side? I found tons of links showing the fuse layout but none of them talked about the location or how to access it. If someone could help me real quick would be awesome!

 

[luv2rallye]

Inside fusebox is in drivers side left kick panel.
Also: http://www.dsmtuners.com/forums/art...-partial-short-battery-drain.html#post1496998

 

[BostonGST]

Okay awesome, thanks so much for all your help!

 

[BostonGST]

Finally found the draw! I guess the trunk does not shut 100% and the trunk light was always on. Thanks everyone for the help! Resolved

 

[1990TSIAWDTALON]

- Stupid hatch light......just like mine. Glad it was a easy fix!!