Not Mazda question..help!
 

We have a 1992 Corolla which I gave to my daughter when she got her license recently.
This morning, the battery was about as dead as a battery can get.
The battery is about a year old. The alternator and all the belts were replaced within
a year also. Yet there is still something draining the charge from the battery.
Any ideas?

Oh, and nothing was left on all night...I checked.

you need to check the alternator to make sure it's putting out the correct amount of power. If it's not then when the car runs it's just draining straight from your battery and not replacing anything...hence your dead battery. Autozone or Pep boys should do a charge test for free assuming you pull it from the car first. If the alternator is good start at the battery and start looking for a short. If you have a bad ground or connection you can have a steady powerloss with no accessories on.

p.s. I failed ASE electrical twice so I'm not going to be much more helpful after these steps!

Thanks Matty!

To troubleshoot a drain on the battery -

Install good battery.
1. Disconnect the ground cable at the battery
2. Use a multimeter between the ground cable and the battery to measure current (milliamps)
3. If the draw is more than a few milliamps (clock, ECU) then somthing is bad.
4. Pull fuses one by one until the draw suddenly drops to a few milliamps. The fuse you pulled will identify the bad circuit (lets say 'cigarette lighter/interior light'). Now you know which components to continue troubleshooting to... Let me know if you get this far.


To test the alternator:
Install good battery.
1. check voltage (multi meter dc/volts) between positive connection and a good grounding point on the chassis.
2. It should read between 11.5 and 12.5 VDC
3. Start the car
4. check volatage again with engine revving to 3000 RPM. it should read between 13 and 15 VDC - if not (no change) it mayt be a bad alternator. Take to autozone for testing/replacement. Retest after installing new alternator.

Questions?
Let me know! (i am a 7-level F-16 mechanic and a fully certified ASE (Actual Shadetree Expererienced) mechanic ;)