Electrical Problem

Jughead · Aug 12, 2010

So heres the story...

I'm 21 and I just bought my first pick-up, a 2002 Mazda b4000 dual sport.
I bought it private after finding it on the kijiji.com The truck ran fine for about 2 weeks, then my battery light came on and I watched my battery meter slowly drop.

After changing the battery then the alternator, the battery still wont hold its charge. I've been charging it at night with a battery charger but when I start the truck in the morning the battery meter is only about 25% of the way up (as if it hasn't charged much, or at all). I've been driving for no more than 20 minutes a day to go to and from work because I am afraid it may die again while I'm driving.

I checked the battery with a voltmeter:
when the truck is off it reads 12.7
when the truck is on it reads 12.3

Does anyone have any ideas?

Thanks.

Mirage · Aug 12, 2010

A couple of quick things come to mind. First it sounds like your Alternator isn't charging the battery. Normally you should see 13.5-14.5 volts at the battery with the engine running. This could be due to a bad alternator, or more likely bad wiring between the alternator and the battery. Check all connections very carfully. Make sure the battery cable clamps and posts are clean (corrosion will prevent current flow). Check the ground cable as well.

If all that is good, then my next guess is you have a major drain somewhere. Do all your lights work? Especially check the interior lights, they seem to be a common cause of battery drains. Do all the interior lights go off when you close the doors. (Inside the glove box as well). Also just for kicks, pull the bulb out of the socket under the hood (make sure it works properly before pulling it out). And check the wiring there.

After you check all that, come on back and let us know if the problem is solved or if we need to dig deeper.

Jughead · Aug 12, 2010

All the lights seem to go off when the truck is off and doors are closed.
As for the bulb under the hood, I'm not sure I have one? (or I just can't find it)..
However my passenger side fog light seems to be burnt out or just not working, should I just change the bulb?

Stxrangerbumper · Aug 12, 2010

check fuse not poped and check belt not crack

Jughead · Aug 12, 2010

fuses look good, and the belt looks fine too

mazda3000 · Aug 13, 2010

maybe your battery just cant hold its charge anymore. any idea how old it is? and if you have a extra one kicking around try it out and see if it changes anything. but make sure your puting a good working one in.

modelageek · Aug 13, 2010

Mirage said:
A couple of quick things come to mind. First it sounds like your Alternator isn't charging the battery. Normally you should see 13.5-14.5 volts at the battery with the engine running. This could be due to a bad alternator, or more likely bad wiring between the alternator and the battery. Check all connections very carfully. Make sure the battery cable clamps and posts are clean (corrosion will prevent current flow). Check the ground cable as well.

If all that is good, then my next guess is you have a major drain somewhere. Do all your lights work? Especially check the interior lights, they seem to be a common cause of battery drains. Do all the interior lights go off when you close the doors. (Inside the glove box as well). Also just for kicks, pull the bulb out of the socket under the hood (make sure it works properly before pulling it out). And check the wiring there.

After you check all that, come on back and let us know if the problem is solved or if we need to dig deeper.

I am with mirage......your running output is to low.where did you get the alt. maybe you should take it out and test it after checking all the connections

kdowney50 · Aug 21, 2010

Troubleshooting electrical problems

This problem sounds like a constant drain on the battery somewhere. Here is how I find the source of that drain:

First, buy a Haynes Manual. The schematics in the back are very helpful.

Then, buy a 12 volt buzzer at a hardware store.

Turn off ALL electrical devices. Make sure all lights are off. (close the doors or push in the door switch) disconnect the radio, etc.

Connect the buzzer in series with the positive battery cable. (Disconnect the positive battery terminal and lay it aside where it will not short to ground. Connect one wire of the buzzer to the terminal clamp on the positive cable and the other to the positive terminal of the battery. (A hose clamp works well here)

DO NOT TRY TO START THE ENGINE DURING THIS TEST!]

Once you have the buzzer connected - and if you have a ground somewhere in your electrical system - the buzzer will be singing.

One-by-one pull the fuses and relays in the Power Distribution box under the hood until the buzzer stops. Once it stops note which fuse/relay was pulled. This will tell you which circuit to troubleshoot.

If pulling the fuses reveals the problem is in the power distribution circuit to the fuse panel under the dash, you can repeat the process to further narrow down the problem.

This test also works with a 12 volt light, or a volt meter. I use a buzzer so I can keep my eyes on the fuse box and still hear when I pull the right fuse.

Once you find the right circuit to troubleshoot, start taking it apart. If, for instance, the running lights are the problem, remove the sockets, look for broken or frayed wires. Hand-over-hand the wires back to the fuse box looking for pinched, broken, or frayed wires. Carefully inspect the socket housings for damage that might cause a short circuit.

If, after pulling all the fuses, the buzzer does not stop then the problem is in the main charging system. Inspect the positive battery cable for damage. inspect the starter wiring as well. If nothing is found, disconnect the starter and then reconnect the buzzer. If it stops, then the problem is likely the starter or its wiring.

If it doesn't, then its most likely the positive cable.

If that's not the problem then I just don't know and you're screwed. :icon_rofl:

Electrical Problem

Jughead

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Mirage

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Jughead

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Stxrangerbumper

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Jughead

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mazda3000

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modelageek

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