Just took my 91 740 wagon to the store. Went in. Came back out. Starter will not work. Nothing happens when I turn the key. A few gauges jump when I turn the key, but nothing else. The door chime rings with the door open, so I guess the battery did not die all of a sudden.
Could this be a fuse?
I tried it in park. I tried it in neutral. I jiggled the shifter around.
That's possible. The radio will not come on. The power door locks work, though sludgy. I plugged a small air compressor into the cigarette light, and it worked, though sluggish.
I put a tester across the terminals, and it seems to have full voltage.
Why won't the radio come on? That's very low voltage.
Could be the battery; they can fail suddenly--could be the alternator or charging system failing to charge the battery. Or a bad connection.
You need to test the battery under load; check the voltage across the terminals without a load first--you should see about 12.6V. If you see significantly less (11.5V or less) either it's not charged or it's bad.
Now, turn on the headlights and check the voltage--if it's dropped below
11V, you most likely have a bad battery.
If the battery voltage isn't dropping, test for differences between the positive terminal and the connector on the positive cable, or from the negative terminal to the chassis. If there's more than 0.5V, you may have a bad cable.
Try borrowing a battery; or jump starting. Also, most parts places can test a battery for you (and usually will for free).
I suspect the ignition switch itself is bad, it could also be the battery cable or even the battery itself. The radio is not any more low voltage than anything else in the car, it's all 12V nominal. It's a low current load, but if the voltage is below a certain point it won't power up.
Well, thanks everyone for your feedback. Under load, the battery was about 6-8 volts. Replaced it and it cranked right up. So, unless there's some other fault that killed the battery, I'm good to go.
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