Battery Light Still On

New battery last month and new alternator today. Battery light on dash still on. All the terminal connections to the battery are clean. What in the hell?

Check the connector on the alternator and make sure you have power and ground there. Also check the alternator and make sure the new one is charging like it is supposed to

I have no idea how to do that. I have multimeter/voltage tester. But I need to know on what setting(probably 20v) and which red and black wires from meter goes on what wire or where and where on alternator to what connection/wire

Simple test for checking alternator output...set your multi-meter on 20V and, with the engine running, touch the Red wire lead to the Pos. battery cable connector at the battery and the Blk wire to the Neg. battery cable. Turn on the headlights and you'll see somewhere in the neighborhood of 14.25-14.5 volts if it's charging.

I can do that but my battery hasn't died yet and the gage on dash the needle sits in the middle as usual but battery light is on. So im pretty sure its charging

Your battery doesn't need to be "dead" in order to run this test. But, I would agree...if the gauge needle is where it's supposed to be, I'd be inclined to believe it's charging.

Aside from double-checking your connections to the alternator, maybe someone else can chime in regarding the battery light.

Your voltage regulator (mounted on the back of the alternator) is what turns off the BATT light. When you turn your key to ON, 12V flows from the battery to the BATT light and then a wire (I think it's green with a white tracer) goes from the light to the alternator, providing the ground for the light. When you start the engine, the voltage regulator turns OFF the ground for the BATT light and it goes out.

Check to see of the alternator is charging by verifying voltage at the "B" terminal on the back of the alternator (large red wire) and then check voltage at the battery. You should see around 13.6-14 volts in both places. If you get good voltage at the alt but not at the battery, you Mega fuse may be blown. It's located on the rear of the power distribution box. As previously stated, you alternator must be grounded to work, but this usually isn't an issue as it's bolted to the engine.

If you don't own a VOM (Volt OHM Meter), you can buy a cheap one at any auto parts store. A very useful tool for diagnosing electrical problems.

I will check these in a little while today. When I check the big red wire on back of alternator where do I place ground? On battery ground?

JusTheUsual said:

I will check these in a little while today. When I check the big red wire on back of alternator where do I place ground? On battery ground?

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any ground is fine (ground is ground), but the battery ground is the best ground you have.

I just checked both. Battery and alternator both 14.25. I looked for a fuse blown and didn't see one blown. Did you mean a relay in the power distribution box instead of a fuse?

Check the megafuse..

It is mounted on the outside of the power distribution box on the drivers side under the hood...It should be a 175 A unit that is mounted between two terminals...I circled it on my power distro box...

JusTheUsual said:

I just checked both. Battery and alternator both 14.25. I looked for a fuse blown and didn't see one blown. Did you mean a relay in the power distribution box instead of a fuse?

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Yeah I never knew about that. I will look at it later. Is it hidden under something like I have to take apart something because from looking at your pic I wouldn't know where to start to take it apart

JusTheUsual said:

I just checked both. Battery and alternator both 14.25. I looked for a fuse blown and didn't see one blown. Did you mean a relay in the power distribution box instead of a fuse?

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The alternator and battery are getting good voltage, so the issue is the wire from the BATT light or something fishy in the voltage regulator that's not breaking the ground connection to the light when it should. Check the electrical connector at the alternator. They've been know to get overheated and no longer make a good connection. As I said earlier, I think the wire for the BATT light is green/wht. You can see free wiring diagrams here:

http://search.ebscohost.com/

use rrcc and rebsco to login

Don't worry about the Mega-fuse as your battery is getting charged.