My '94 mazda b4000 recently lost electricity to the cab and the engine won't turn over.

I will get in, the seatbelt beeping will start, then that will stop. I will put the key in the ignition and nothing happens.

I put a voltmeter on my battery and its registering 12v (which is a bad but usable battery i think).

I checked the under hood fuses and all look good, but i have no way of knowing if the relay's are good

The under-dash fuses are also mostly ok, one was burned out, but i replaced it and nothing helped.

I also tried to jump start it, and nothing came on in the cab and the starter didn't turn over, although i only tried for a few minutes before deciding that i would have seen some lights come on by then.

What else can i check? I need it running to get it to the mechanic :(

edit: As of this morning, if you let it sit, the dash will get power, and the radio and heater will come on if you turn the key a bit. Once you try and engage the starter, you will hear a brief click (doesn't even sound to me like it turned over all the way) and then everything will die for a few minutes again

edit2: I have charged the battery (currently reading 12.8v up from 11.8v) and it has not changed the situation.

2 Answers 2


It sounds to me like a dead battery.

Depending on how accurate your voltmeter is, what you see as 12V may be 11.9V or lower. To give you an idea, an open circuit battery terminal voltage of 11.7V indicates a completely uncharged battery.

What you are describing happened to me once with a Volvo car, due to a faulty switch in the glove-box; the glove-box light was on for days and drained the battery.

It turned out that it was much cheaper to purchase a light-duty car battery charger than having a mechanic visit, let alone towing the car to a repair shop. I just left the charger do its job for a day or so and everything went back to normal. I got my car fixed for 60 euros or so, and got a car battery charger for free...

  • Ooh, it was 11.8 or 11.9 i think (was rounding up). I didn't know it was that sensitive. I will get it charged and try again. Thanks
    – Chris
    Commented Jul 14, 2012 at 20:04
  • Battery is reading at 12.8 and it still won't start. Only noticeable difference is that when the cab briefly dies after it tries to engage the starter, the cab comes back to life much quicker.
    – Chris
    Commented Jul 16, 2012 at 13:14
  • @Chris My money is still on the battery. Hook the volt meter up and see what the battery voltage is when you try to start the car. If the voltage drops below 9.6 volts then the battery is bad. See my post here for more info on checking the battery Commented Jul 16, 2012 at 15:29
  • @Larry, ill do that when i get home. Are car battery's much different than truck batteries? IE can I pop my car battery into the truck to get it to the mechanic without hurting it? I can't really see how it would.
    – Chris
    Commented Jul 16, 2012 at 15:51
  • @Chris As long as it will fit physically and they both have the same type of posts Commented Jul 16, 2012 at 16:24

You should also check the battery connections. Make sure they are clean and secure.

  • +1 for checking connections and cables. I'd specifically look at the ground side. Be sure the ground strap connecting the battery to the body is in good shape.
    – mac
    Commented Jul 17, 2012 at 14:58

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