Alternator wont charge, & tach is off

[tompumped]

I'm not sure what's causing the alternator not to charge on a 93 6.5 td. I'm going to go back out and check the rest of the circuit out.

So far I checked all the fusible links I could find and they were good. I didn't know where the alternator one was so I tested all of them. I know I could've just checked for continuity from the chargine wire to bat + but I wanted to be sure.

There are only two wires left to check, the wires for the voltage regulator plug. I know one is good, because the gauge still reads properly. I guess the other wire is what provides power to the regulator to get the alternator to charge? When the engine is running I get battery voltage and my father said the tach is off. thank you

[DmaxMaverick]

Welcome aboard!

The tach is driven by the alternator (one of the "other" wires). If you are having charge issues, and the tach doesn't work, it's almost always a bad alternator. If/when you replace it, make sure you have the correct size pulley, or the tach won't be accurate.

[DennisG01]

I had a similar problem (although I don't think the tach was off) and it turned out to just be a loose connection at the battery. Visually it wasn't loose - but I could physically rotate the cable around the post. I would try that first - remove the cable at both the battery and alternator, clean and reinstall. It may not solve your issue, but it's always good to start with clean and tight connections.

[tompumped]

After going a little crazy trying to solve the problem cleaning all the battery connections and grounds, checking the fusible links and fuses. My father tells me that he moved the gauge cluster when he installed a radio. If i'd known that before I started I would have went there first.

It turned out to be that right where the plug connects to the cluster one of those thin copper contact tabs on the cluster side was folded under itself on the corner so it was either not making a connection or it was barely making contact. The gauge still worked, it was just reading battery voltage and not charging. I found it when I went to check for continuity in the brown wire and I almost overlooked it. I found out my problem was with the brown wire because when I back probed the connector and applied voltage to that pin the alternator worked. Iirc it was pin A on the cluster plug

The tach would not read under 1500 rpm. I didn't know that pulley size would affect the tach signal.

Thank you guys. Now it's on to the four wheel drive. Hopefully that's easier.