No cranking, all of a sudden

Jiggle the battery terminals. The have to make a GOOD contact.

Regards,

Boris Mohar

Got Knock? - see: Viatrack Printed Circuit Designs (among other things)

void _-void-_ in the obvious place

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. Find the main fuse and reseat it.

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

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).

Gary

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.

I had the same type of problem -- bad battery. Under no load it was

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.