Bad alternator.. or something else?

[guidoverduci]

Hi! Battery is not showing a charge while engine is running, before I replace the alternator... is there anything else I should check? It’s a 351W with serpentine setup. Thanks for any advice!

 

[68Broncoz]

Check fuses between alternator and battery? Also you are getting power to the alternator from the ignition switch?

 

[blubuckaroo]

You can find out whether it's a bad alternator or regulator by full-fielding the alternator.
To do this you simply jumper from the battery positive to the "F" terminal on the regulator when the engine is running.
You would have a volt meter across the battery to see the voltage change. If the voltage increases to 17-18 volts, then you know the alternator is good.

 

[gnpenning]

Don't forget to disconnect the regulator before doing the test.

 

[Steve83]

Battery is not showing a charge...

The battery has no way to show a charge. What exactly are you looking at? It takes an expensive meter like this to show how much charge the battery contains at the moment:

(phone app link)


But it only takes a digital voltmeter (with a good battery) to check if it's BEING charged. Clean the battery posts (AND the clamps around the posts) down to shiny metal, and take some readings like these.

(phone app link)

...before I replace the alternator... is there anything else I should check?

Everything mentioned & linked in the captions of this photo album:

(phone app link)

...with serpentine setup.

The belt isn't actually very important. But the TYPE of alternator is. Post pics of it, and both ends of its charging wire, and its voltage regulator, and...