Electrical Problem - Battery Drain

Hello,
I have a 2000 Cavalier having electrical problems. The battery drains every few days and won't start. I have a new battery and have had the alternator check serveral times. After the 1st time it happen the radio quit working. I have hooked up a test light between the negative battery cable the the negative post on the battery and then started pulling fuses. I pulled all fuses from the inside fuse box - light stayed on bright. I then pulled the wires from the alternator - light stayed on bright. I then started with the underhood fusebox - found that with 2 fuses pulled the light goes out. One fuse is a 40a Batt1 and one is a 50a ABS. The light only goes out with both fuses pulled.

Any suggestions on where to go from here would greatly be appricated.

Thanks, Sal

 

How did you test the alternator? Those typical Autozone type store tests are not completely reliable.

You will always have some current being drawn on the battery with the car off.

You need to have a load test done on the battery to see if there is actually excess amps being drawn.

 

I had the alternator tested by 3 different sources - autozone, Orileys, and walmart. All tested good. I then tried another test that I read about - I unhooked the positive battery cable while the car was running - the car stayed running and didn't stall.(this was suppose to indicated the alt is good??). I also unhooked the electrical connection to the alternator with a test light hooked to the neg battery cable and the light stayed on bright. I also purchased a amp meter that goes into the cig lighter socket. While driving I can see that it maintains current - although the fan on the a/c runs slow then fast and only speeds up when slowing down for a stop sign. Does this sound like a bad alternator? - I have no problem changing out the alt, I just of course, don't what to change it out and then have it be something else causing the problem. I have already changed out the battery and it wasn't it.

The only time the test light between the neg bat cable and post went out is when two underhood fuses were pulled - a 40a Batt1 fuse and a 50a ABS. With my limited knowledge of auto electric, I am now thinking the exact problem may be within those curcuits some how. I see from the elec schmatic that the ABS curcuit goes to the Electronic brake control module (EBCM) and the Batt1 goes to the inside fusebox.

Thanks for the reply - all help is greatly appricated.

 

You mean the radio quit when simply turned on to acc. for example? What about other stuff/lights?

Could something like the trunk lid light be stuck on all the time? Have you gone out in the dark to make sure all lights are off, under hood, key lights, trunk light, etc? Or indicator lights for things like seat belts or whatever?

Do you have another battery in another car you could swap out for over night and take before and after voltmeter tests?

BTW, if your battery terminal voltage as read by a voltmeter at the terminals shows about 12 volts when the car is off, but then reads about 14.5 volts give or take, when you run the car, I'd guess the alternator is probably good, myself.

 

I've got a 2000 cavalier and have had lots of problems with the door switches. I finally disconnected them, and no problems. Maybe check that.

 

Yes, radio quit working, but came back after a few times after disconnecting the battery to recharge it. I’ve been troubleshoot this problem for a few months. Bought the car from a dealership for my daughter for her 1st car. It was OK – till I didn’t drive it for a
few days. Then got in it and found battery dead, had battery tested and replaced it. Now I am still trying to isolate the problem before I start replacing too many items.

I looked everywhere for a light on (trunk, dash, dome ect), also for any loose wires.

I will try swapping out the battery though, and check the battery terminal voltage with car on and off as you suggested. I will be working on car all day tomorrow.

Thanks much for the replies, I got a few more things to look at now, since I found that the ABS and Batt1 fuse seems to take the test light off – I’m now researching a Haynes manual for answers to check out that circuit (think I need better manuals – public library here has a Mitchell on line database that I haven’t check out yet.

Junglejim – how exactly was your door switches causing you a problem (battery drain??), and how should I check them.

Thanks again – all input is very much appreciated. I will continue to post any results I find.

Junglejim

 

Can't wait to hear back from you. Running down electrical problems can be both time-consuming and rewarding if you find the problem. Mitchells wiring schematics in the libraries reference dept. (can't check these out but you can photo copy the pages as I have pages copied for all the vehicles I have) can be most helpfull, as they also tell you the colors of each wire; plain colors and striped ones, and this makes the job much easier.

 

I think you have it narrowed down with the light,now you need to go the next step. Like OKC said some draw is normal, like an amp or so. If you can get a AMMETER conect it where you had your light,then pull your two fuses one at a time. Good luck RW

 

I have 2 multimeters, but don't know how to use them, been trying. Tryed radio shack and serveral dept stores to get a ammeter (assuming it is just one easy operation) - store seem to only sell multimeters. Any one know where I can get just a simple ammeter. I'm near Oklahoma City.

Thanks retired wrench, I got a feeling I going to be tearing out lots of stuff to get to wires.

Sal

 

MULTImeters have a ammeter built in. You have put the selector on mA and I believe move one of the test leads to the other spot.

 

thanks, hotinOKC

my electro-tek multimeter has -mA located in the lower left which looks like 3 settings - 0.5 , 10 , and 250. Would you be able to tell me about those 3 setting - which one I should use and which arc to be reading. (analog scale).

Also, would I just be better off investing in a digital meter for this kind of troubleshoot.

thanks again

Sal

 

This is actually a milliamp setting and is commonly used to see if electrical current is being created at flame generators like when pilot flames heat up thermopiles. One milliamp is only a thousandth of an amp. 250 milliamps would be 1/4 amp. On an analog meter if you had it set to 250 and you did get 1/4 amp, the needle would point all the way to the right. And at that setting, if 125 milliamps was being generated, or 1/8 amp, the needle would point straight up to the middle, etc.

[BTW - IF you went ahead and tried the mA settings, you would always want to start it at the 250 scale just in case of higher amp draw, to help protect your meter against the voltmeter's needle from burying to the right. And IF say you were to see that your needle only moved a smidgeon from the off/normal left position of the needle, THEN you can click the mA setting down to the 10 setting, etc.. But like I said, I'd be leary of using this mA setting for your application, IMO. I'd just use the DC volts setting (set to 50), as that will show you if a particular wire has any amount of 12 volt current going through it.]

If in your testing you tested some wire that had almost full battery voltage going through it, by accident, I'm not sure what this might do to your test meter (if on the mA settings) because the reading would fly to the right and 'bury', if you know what I mean.

If I were you I would first try to use someone elses or a different battery, and take before and after readings; 'before' would be after your battery was charged up after car useage, and 'after' would be say hours later. You would use voltmeter set to DC volts to the 50 volt setting and compare voltages, where the needle points, before and after (like if yo had 12 volts at first but only 7 volts hours later) .

A regular big box store home ammeter is not going to work for you, unfortunately either as these are made for higher amp draws/AC current. Unfortunately also, with such a meter, all you have to do is open the jaws and let the wire in the loop for testing. A convenience I'm sure you would like to have - but this will not work for you. Advance Auto guy told me they don't have such a tool for the DC 12 volt systems though.

My Advance Auto recommends that since they sell no DIY type testingmeter for finding 12 volt smaller amp leaks and that pro-equipment can run a couple hundred he said, that you first try the battery swap, and then as long as you don't have emergency issue, you could try pulling out one fuse a night and test volts at battery before and after, and do every fuse this way in succesive nights and hope you narrow down what circuit is causing this.

Or if you are in a hurry you may have to test wires with the voltmeter set to 12 volts and see what wires show voltage traveling through them. But THAT will only help you if you absolutely know whcih wires are NOT supposed to have voltage going through them when the key is off, unfortuantely. There are things in the car drawing small current even when the key is off, like computer, clock and ?

I told him that I used to use one of those wire insulation puncturing ice-pick like tools that lights up to find if current is going through the wire and he said that that is an effective tool except you have to realize you are puncturing wire insualtion, and depending where the wire is located, like under the car where salt can get at it, you can trigger corrosion, so keep that in mind, - or if you did use such a tool - to seal the hole with say sealant or electrical tape.

Keep us abreast of your situation.

 

A constant drain of "one amp or so" will drain your battery in a short time. As far as I know, any drain over 50 mA is considered excessive (this is 1/20 of an amp).

 

That's true. What is a shame though is that they don't sell (that I am aware of, reasonable, to the home mechanic) a fractional amp testing device just like the halo type ones sold for a/c voltages. The advantage to such a device lies in the fact that it doesn't matter if you have major current going through the wire or not, without thinking you might do something to your test meter (if you start out on the higher setting). AND, you do not have to try to find a good spot where you can disconnect wires in order for you to make CONTACT with the test lead probes and car wires like you would with a voltmeter.

Has anyone here used the milliamp settings on a voltmeter to actually successfully find such leakages? I could be wrong, but to me it seems like it would be quite the arduous task.

 

did you ever figure out your problem?
i'm having a similar problem with mine. the battery drains within 3 to 4 days if i don't use it.

 

oso,

What have YOU checked? Have you tested or had battery tested?, or alternator/belt, first, before concluding there is leakage somewhere? And have you made any tests for leakage?

 

i have already switched out the battery along with the alternator and belt. if i don't move my car over the weekend. there's a chance that the car might not start come monday morning when i have to go to worl. on sunday nights, i usually run the car around the neighborhood as a precaution to make sure the battery is still charged up for me.

 

Have you made sure you don't have any lights that aren't shutting off?, like trunk or hood light, or any lights in the car (by looking at night)?

Is the car stock?, where you have not added any elelctrical components that are wired direct with it's own switch? Other than insulation wore off on wires that then short to metal, the idea of some light on or some switch on that is not shut off are what come first to my mind.

And do all your electrical components work, like your horn - everything? Because suppose you find something electrical that is not working; In theory, the reason why it might not be working is current is going to ground prematurely. So make sure everything you do have, works.

 

I'm still working on it - I haven't had a lot of time to devote to it.
I have the dash trim panels outs right now where I had been checking
current in different wires (been this way for two weeks) and the car has
been sitting and surprizingly every few days I go out to start it and it been
starting up. My next check is going to be the A/C fan. It hasn't been running right.(blows high a first - then almost stops on high speed - then randomly blows hard) Though I would just change the fan and fan actulator (elec connection to fan) out next chance I get since they don't cost too much. Then I think I put it all back together and drive it for a while and see what happens. I will continue to post with any updates.

 

Electric fans have two speeds, high and low. Depending on engine temp, it will adjust accordingly so I doubt it's the fan.

 

Your alternator has a "isolation diode" in it that I'll bet is leaky. After a drive (when the battery is strong) disconnect the 12+ cable going to the alternator. Leave it off and see if she starts the next day. If it does start, I would think that would confirm a faulty alternator.

 

HotinOKC - are you referring to the cooling fan under the hood? I was referring to the A/C - Heater blower fan in the interior. With the A/C on when I first start out I put the fan on high (has 4 postions) and it will trickle down to almost no air at all and then blow hard every now and then.

Jeffreyclay - I had the alternator bench tested at autozone and they said the diode's were all good. Could that test be missing the "isolation diode".
Do I disconnect the 12+ cable "at" the alternator? Is this the positive battery cable? Also you say leave it off and try to start it the next day and if it starts then the alt is bad? Could you explain that a little more plz. I would think that with the cable unhooked there would be no power to start anything. What am I missing or misunderstanding?

Thanks, sjames

 

Well, I think I still have electrical problems, but have made some progress (I think) with the limited time I have to work on this.

About a month ago, I took the radio out. Then every 3-4 days I would go out to start it and it's been starting up with no battery drain. Maybe the radio itself is bad (??).

Two days ago I replaced the A/C Blower fan and fan resistor. Now the fan blows good on all 4 speeds. But - here come the but - in the highest positions - 3 and 4, the service light, theft system light, trac on light, and check guages light come on and the guages (fuel, temp and speed) stop working. (?). So If I just leave the blower on 1 or 2 postions everything is OK, no lights - but almost a soon as I switch to 3/4 those light come on.

Seems to happen more often when I'm braking. And If I driving at night (with lights on) the ABS light comes on also and the car hesitates (like it wants to not use the transmission no more).

So now I thinking >> no 1 - the more elec components I use the worse the problem - short somewhere? -- and -- >> no 2 - sometimes while backing out of my driveway I go to brake and hear a "clunk" while braking - like it's coming from the rear axle or rear brakes. - rear brakes - possibly electrical ABS connector on wheels?? -- and now no 3 -- >> This car is a very basic model - no power win/locks or anything - and no "theft system" - but I have a theft light that comes on - so I,m thinking this theft light has to do with the radio being removed since these factory radios have some sort of theft system code.

I got a feeling - I'm going to get quite an education working on this car. But I am determined to get to the bottom of this.

I figure my next round will be to throughly check out the abs system, rear brakes and test the electrical connectors at each wheel. Then depending on what I find - replace the radio and check it out from there.

One more thing - Twice the check engine light came on and I pulled these codes out of the on board computer while all this was going on the last couple of days:
P0171 - System too Lean, Bank 1
P0440 - Evaporative Emmision System, Bank 1
I erased these codes after I pulled them and drove about 60 miles
so far without any codes.
I am considering purchasing a factory service manual - found a few sites
that sell them for about 60 bucks.

As always - any and all comments, suggestions, or otherwise will deeply be appreciated - and I will continue to update and hope when I resolve this problem it will help others.

thanks to all, sjames

 

Ya-hoo This turkey if fixed.

I'd like to say I found the problem, but I gave up and took it into a Auto Shop. Lucky for me they were honest and found
the problem right away. It was the battery negative post needed to be grounded to the frame of the car. The cable ran from the negative post to the engine as it was, but it also needed another ground wire running to the car frame from the battery post. The shop hooked it up with the running lights regulator box located just inside the front after opening the hood. This stopped all the electrical problems.

As a diy'er I'm a little surprized that I could find this anywhere in manuals. I went back to the haynes manual and studied it - but no extra ground from the battery that I could see.

Hope this helps anyone having this problem.