My Comet won't start. If I jump it, it starts. When I turn the key on just enough to turn on the panel lights, the oil and alternator lights come on: the oil light is bright but the alternator light is not bright. I tested the battery and it reads '12.59'V just like my other vehicle's battery tested at. I bought new battery cables but that didn't help. When it's connected via jumper cables, the alternator lights are much brighter. What should I try/test next? Thanks!
This thread will probably moved to the technical sub-forum Lika... It sounds like you have a bad battery, but these symptoms can mean a number of things. The voltage test on a battery is not necessarily indicative of a good battery's ability to produce full load AMPS. In other words, a bad battery CAN show a full voltage, and still be bad, in respect of not being able to produce enough amperage. If your car starts with jumper cables hooked to your existing battery, then the first thing I would do is replace my battery with a new one, given a load test by the seller.
Clean terminals and battery again very well, use wire brush or sand paper and make contact area shiny. With battery charged and cleaned, see what voltage you have. Turn headlights on with engine off and rechek battery, If volts drop much battery is probably bad and should be checked
Good point. I missed the possibility of the battery terminal connections being corroded. Good idea to check this before spending the money on a new battery.
Good point about popping on the headlights ... If you turn on the headlights and they won't come on, or are dim, it is likely that you have a battery or cable problem. If you turn on the headlights and they are bright, and the car won't start, then you need to look at the solenoid and starter for where the trouble is.
I got a new battery, seems like that fixed the problem! Hope it keeps working and I don't get stuck on the street somewhere any time soon!!
Have your charging system checked, if you haven't already! Most auto parts stores will do this free, especially the one you brought the battery from!