My car didn't start this morning and when I checked the voltage across the terminals it was 12.4V.

What should be the nominal voltage across the teminals ?

 

12.4 volts is normal. When you start the car it should go up to 13 - 14 volts. Might be something else.

 

Need more details. What happens when you turn the key? Does it turn over? Do you hear a rapid clicking? Nothing happens?

 

My battery died about a year ago, checked the water levels and found they were low. Filled battery up with distilled water and recharged, it's still good to this day. HTH

 

Actually, after reading the previous post that the voltage is fine, I went ahead and cleaned the terminals with brake cleaner and then cranked again and it started. Went to the local store and tested the battery and it passed the test. So it isn't the battery/alternator.

I am begining to suspect the ignition switch or the starter (which incidently turns over the motor like a champ). But then I don't want to be stranded somewhere without the ability to turn the motor over.

Any suggestions where I should begin understanding the problem.

 

Admin: Is there a way I can change the subject of the thread.. looks stupid on my part to come up with such a dumb subject?

 

It might be your starter contacts. How many K is on your car?

 

voltage does not start your car. Just remember it like that . It's called Amps. Our cars are 550 CCA (cold cranking amps) at 0 F i believe and worm it goes up by about 100 a so 650 amps. Now in California and wormer states they don't have CCA it's called something else.. I forgot.
Water from your electrolite goes down so it would benefit from a distilled water top up to full mark. But for that you have to take the black cover off.
Now in your case since they tested the battery and it passed battery is fine but most likely in between your terminals and posts there is corosion or other deposits (sulphur from H2So4 in your battery). So it;s not making a good contact. Take off terminals and clean them with a brush and then put them back. That might solve your problem if battery passed.
Oh and also wipe your top battery as if you have oily residue current will jump between posts and you could have a draw. Draws should be less than .5 of an AMP. That you neet to not worry i hope. PM me on what happends

 

see you fixed your own problem. Still take them terminals off then and clean them

 

I have close to 120K and it runs like new -- touch wood!!

Coming what NisTech said, there was oily residue all over the battery and since I had taken it out to be tested, I cleaned it nice. Never realized current could jump between terminals with oil being the medium. Good.