Cascade Crew

Al Hasse · Posted: Mon Oct 10, 2011 11:12 am Post subject: New alternator not charging

The alternator I had was working except the shaft bearing was going away. I installed a new (reman) from NAPA and can't get it to charge. With the car running, I have and the 2-wire connector unplugged, there is 12V on both wires, this compares with the V6. 12V at the charge post with the engine off and only 10V with the engine running. I had the alternator tested just to prove or disprove it faulty, but it tested fine. I have a feeling a fusible link opened, but not sure which one.

aaron_sK · Posted: Mon Oct 10, 2011 12:50 pm Post subject:

If you suspect a fusable link get down there and pull on them. If they are bad they will stretch or break.

Al Hasse · Posted: Mon Oct 10, 2011 1:52 pm Post subject:

What confuses me is that I have voltage everywhere there is supposed to be voltage, and when, except at the output lug. That should indicate that all three fusible links are good, or at least have voltage on both sides with respect to ground.

The one at the junction block, which goes to the output lug from the battery, is good. I haven't gone under the car to check the other two (one from starter to alt and the other from starter to ignition switch), it's a bit wet in the driveway.

Alphius · Posted: Mon Oct 10, 2011 2:45 pm Post subject:

I've seen a fusible link fail enough to cause problems but still show correct voltage under no load. Damn hard thing to troubleshoot. Al, you of all people should know that a circuit can have decent voltage under no load and still have a poor connection. Wink

Don't rule out the alt being bad again, one time I went through three parts store alternators before I got one that worked right.

Al Hasse · Posted: Mon Oct 10, 2011 3:14 pm Post subject:

I'm not discounting the alternator, though it tested fine at NAPA. I finished looking at all the fusible links and they appear to be fine, no stretch or break while pulling on them. Other than the alternator itself, all I can think of is harness pigtail with the red and brown/white wires. The red wire is hot always as it should be and the brown/white is hot in run as it should be, but the alt still refuses to charge.

chevymad · Posted: Mon Oct 10, 2011 4:42 pm Post subject:

Your old alternator always charged, but had a bearing problem, and the new one doesnt charge? You have battery voltage going to the regulator and the main post? If the main post fuse link was bad you'd have high voltage on the lug with the engine running.

I say you have a bad alternator. Not sure about other parts store parts, but at times napa electrical is severely crappy.

Al Hasse · Posted: Mon Oct 10, 2011 5:41 pm Post subject:

Thanks Brandon, I'm thinking the same thing, especially since my old one charged and all I did was drop another in and it doesn't. Since NAPA's hours and my hours are about the same, it's going to be next weekend before I get to try another.

Al Hasse · Posted: Sat Oct 15, 2011 3:13 pm Post subject:

Success! After getting two from NAPA that fail to charge, the third one I got from O'Reilly's charges at 14.75 volts. Time to warranty the NAPA alternator I still have.

Dv8 · Member Joined: 05 Mar 2010 Posts: 108 Location: Ruston WA

I hate NAPA alternators!!!!!

kutison · Posted: Sat Oct 15, 2011 4:33 pm Post subject:

Good, this sounds familiar. My battery isn't being charged. Just took my battery in to NAPA and it tested good., while testing bad at NAPA.

kutison · Posted: Mon Oct 17, 2011 10:42 pm Post subject:

And my new NAPA alternator isn't working either.