Battery not charging, alternator tests ok

[Cutter]

I dropped my alternator off at a shop for a rebuild, it took 6 weeks for me to get the all clear on it, so what do I look at next to figure out why the charging doesn't work. I put a brand new ground strap on already, I suppose I will change the positive leads as well.

[SalemRover]

Did you take any voltage readings at the battery when the alternator is running? Make sure you measure from the actual battery positive post and not the wiring. The reason for this is to isolate any possible contact issues between the alternator and the battery. Personally I did have a loose positive battery terminal that caused what you are describing. Good Luck.

[Cutter]

Did you take any voltage readings at the battery when the alternator is running? Make sure you measure from the actual battery positive post and not the wiring. The reason for this is to isolate any possible contact issues between the alternator and the battery. Personally I did have a loose positive battery terminal that caused what you are describing. Good Luck.

I did and it wasn't getting any input- started at 12.8 with a new optima, and I watched it drop. I'll remount the alternator and try again just in case once I pick up the part.

[LaneRover]

Are you saying it took 6 weeks for them to fix the alternator? Ouch!

[Cutter]

No it took 6 weeks for me to call them, they said they called me (but didn't). Its ok I didn't have time to do anything in that period anyways.

[Terrys]

The heavy brown wire (about 8 gauge) should run from the alternator to the Battery terminal on the solenoid. I'd check the condition of the connections. I remember working on a non charging truck where the owner, when replacing his solenoid, had inadvertantly connected the heavy brown wire to the starter terminal instead of the battery terminal.
If you're going to replace the + cable anyway, get one that has the accessory cable molded into the terminal, and run that directly to the alternator.
As an afterthought, does your charge light come on when you turn the key on? Does it stay on or go out when you start the truck?

[Cutter]

The charge light would go out, but did come on.

[I Leak Oil]

If you put your meter on the output stud of the alt. while it's running what are you getting? Does it change when you rev the motor?

As Terrys mentioned, run a wire right from the alt. to the battery. It'll bypass any other connections and is very reliable.

[TeriAnn]

I dropped my alternator off at a shop for a rebuild, it took 6 weeks for me to get the all clear on it, so what do I look at next to figure out why the charging doesn't work. I put a brand new ground strap on already, I suppose I will change the positive leads as well.

You know I had an alternator that worked fine for years but stopped working somewhere around Monument Valley. Drove me crazy as I tested, bypassed replaced pretty near everything including new ground straps & new battery cables when I knew they couldn't be the source of my trouble.

Ended up that the metal bolts going to the metal brackets going to the metal engine did not make a good enough alternator ground. The cure was a wire from the alternator case to frame ground. Alternators have a threaded hole for a ground connection. Hardly anyone uses it when they convert to an alternator.

Drove me crazy trying to find the problem.

[Cutter]

Alright, I replaced the positive lead, cleaned all the connections and it works fine. Thanks for the help, not sure what the end culprit was but all that matters now is it works. Today was a good day, got my dash all back together, new volt and vacuum gauge sorted out and working, and am finally ready to hit the road again. Though my swivel ball is weeping....going to ignore that a bit longer so I can remember what it is like to actually drive the damn thing.