Lissav

The EG died on the highway last week. Alternator went and i had been driving on battery power for some time now. I got a new alternator, i put it in, i boosted the EG and drove around the neighbourhood for a bit, the battery light still on though. I don't want to risk driving around for it to fail again and waste another tow.

CN: Brand new battery was bought and put in, alternator dies & drains battery, changed alternator, drove around, battery light still on. WTF?

fastrc2

take a voltmeter from ground to the main thick cable on the alternator whats the voltage? also set it to ohms and check from the positive on the battery to the same point at the alternator if its anything over .5 i would check the cable further, wiggle it and see if it spikes to open or a higher resistence, check if your alternetor has a fuse in the fusebox. the reason why the amount of voltage at the alternator is important, is becuase the alternator actually needs to take a little power for it to make any. also dont run it all the time on a dead battery when you get it charging, youll burn up the brushes or at least shorten their lives. a if you unplug the plug that has the small wires at the alternator does the light go off?

B serious

iTrader: (1)

If you check for resistance, DO IT WITH THE CAR OFF.

Dont check the resistance between the battery and the ground. You will most likely blow your fuse in your multimeter.

There may not be a good connection from your alternator to your battery. Make sure that your battery cables are tight and in good condition

There is a ground going from the trans to the chassis. Check that. This is a very common cause of a tirade of electronic issues.

Check your fuse for your "ELD" or electronic load detector. If that fuse blows, the alternator will not charge the battery.

Make sure that the white wire coming from the alternator goes back to your passenger side engine bay fuse box and connects well to it's terminal inside there.

Make sure the alternator connector is in properly and snug.

Got enough belt tension?

Belt in good shape? As crazy as it sounds, my friend's belt was tight, the alternator was good, but it still wasn't charging. The belt was just worn out so it wasn't turning the pulley adequately. We changed the belt, and it was good as new. It was on a POS 90' prelude. So it took 50 years.

Try testing the alternator. Sometimes, rebuilt units aren't rebuilt well...or they are damaged during shipping or whatever. There should be around 14ish volts at the alternator termial (big white wire).

fastrc2

also i have heard of on some models under the intake, about 4-6 inches fromt he alternator the cable fromt he alt. sits in a bracket, and this bracket can rub through and cause an intermittent short to ground that drops the voltage, but the short to ground isnt a high current so it doesnt melt anything. also when i said check the resistence of the cable, i meant always going from a positive to a poitive, or a ground to a ground, never ohm ground to power, but if its the ground to ground or power to power it doesnt matter if the battery is hooked up or if the car is running. basically the point is to check for the path for charging electricity to be able to move freely to the battery.