no i know the idle/rev issue for the light. the connectors on the back of the alt that push on and dont get tightened down were loose. Swapped connectors and got some nuts and its good to go. ok so the problem is not fixed. Car was dead this morning Not fun since its my daily driver. So either the battery is draining or something is drawing power while the car is off. I drove it around all yesterday and even left it for a couple hours so it must be charging while driving, as the test at advance confirmed. I guess the only way I can think of to test which is to charge the battery until I can start my car then unhook the leads to it and check it the next day or 6-8 hours later and see if its dead or lost a lot of power. If it is the battery then what could have killed it since its new?
To check for something draining the battery, I would pull a battery cable and, when not in a bright light, with the ignition off, touch the cable to the battery terminal and look for a spark. If you're getting a substantial spark, something is drawing current. If there's no spark, or the spark isn't real aggressive, you can connect your ammeter between the battery terminal and the removed cable. Depending on what devices you have, a draw of .050 amps or so might be ok. If its much more than that, or if you got a substantial spark, remove fuses one at at time and retest and you might find a circuit that's drawing current. The battery might have an internal short which wouldn't be detected that way.
No more risk than removing/attaching the battery cables to the battery. All I said was look for a spark when you do that. Just thinking about your ammeter if something is drawing more current than the meter can handle.
Your first step should have been to CONFIRM that the battery is good. New or Not. Ive sold many batteries over the counter and I have seen some bad off the shelf, bad in weeks or months. Do yourself a favor and rule out the battery. Take it out of the car and let the parts store fully charge it and then load test it to see if its good. shold take an hour or less even if the battery is fully drained.
ok so battery tested good exchanged it for a new one anyways. Something is draining it. i can leave it for a couple hours and itll start up but over night and its too low. Happened last night again. Ill give the spark thing a try. Is the only fuse box the one under the dash on the firewall?
Give the new battery a chance. Ive done thousands of battery tests and can tell you they arent al accurate. and I can test a battery right after charge and it tests good, then let it sit a while and retest it and its bad. Many of these new little handheld testers we get in the stores just dont give consistent results like the old big BAER load testers. But the spark test may show you something. If you put a voltmeter on the battery with the car off and see it dropping very slowly then get in and pull a fuse at a time until it stops. Only fuse panel is under the dash.
Makes more sense to pull the battery cable and put an ammeter between the battery and the cable and see what the current draw is. Then pull fuses until the current drops. The result is quicker. I had this same problem in a minivan once. Found out one of the lighted mirrors built into a sun visor didn't turn off when the visor cover was closed. Current draw was about 1 amp, just enough to kill the battery overnight
I had this issue once and it was the brake light switch. It didn't pass enough current to have the lights come on, but it would drain the battery overnight. I'd recommend just taking off the negative cable when you park for the night. I did that for a week until I found out where my problem was!
a bad diode in the alt. can drain the battery when the car is off. pulling all the fuses will not find this. you need to detach the alt power wire to see if the drain goes away.
which one is the alt power cable? I remember when the problem first started the bottom push on wire that goes to the voltage regulator i believe would spark when being removed when the car was off. Which wire has the diode. I suppose ill leave the battery cable on and disconnect all the alt wires and see if it drains the battery. Also the brake light think may be my problem as before my brake lights would sometimes stay on.
I read this entire thread on the edge of my seat, waiting to see what the trouble was aaaaaaand, it ended! any update?
I believe its a bad diode in the alternator. Only one wire with the car off sparks as i mentioned above.
