This week I've noticed my battery voltage gauge stays low for up to 1 minute after starting the engine. When I say low, I mean it hovers on the low line of the normal range. After a minute or so, it goes up to the middle of the normal range, where it has been for years. Is my alternator failing? No weird noises or anything, and its spinning as normal. I grabbed a voltage meter to check the battery, but my the time I got back to the truck with the meter, the gauge was up where it should be, and my meter showed 14.1 volts. Has happened 3 times this week. This morning, it went straight to the middle as it should. Ideas? It is the factory alternator from 1997 (yes, i am the original owner)

And if I do need to replace the alternator, is there a brand to stay away from?

 

Cheap things. Tighten/clean all cables, grounds etc. First.

 

Most auto parts stores will test it for you for free as well.

 

In 2022 I repalced all the battery cables from the battery, all the way to the termination point with #4 welding cable, and new military-grade lugs on the battery. In 2023 a new battery.

Never did connections at the alternator end though.

 

Alternator brushes might be on their last leg. If the alternator is otherwise in good condition, and parts are available, might not be a bad idea to rebuild it.

 

Yeah, thanks for that. I called a reputable alternator shop and they said $150 to rebuild, and he highly recommended rebuilding as opposed to replacing with parts store unit. Discontinued from Mopar, so I called a parts store and a no-name alternator is $173. Guess I'll get it re-built if turns out to infact be the alternator. It couldn't be an ECU issue, telling the alternator not to charge?

 

Check your voltage with the vom, Dash gauge is not always correct. Also check that the tentioner is keeping the belt tight(they like to stick).

 

Ok, will do. I got called out of town for work, so I won't be able to look at it until next week. Will report back next week. Thanks for now, Gents

 

I checked the tensioner and it appears fine. Took the tension off and the alternator spins as expected. So then I figured at this point I have nothing to lose so I hit the alternator with compressed air and blew it out from every direction. Got quite a bit of dust out of it, and for over a week now the gauge is acting properly. I'll update if/when things change. But yeah, I imagine a rebuild is not too far away but for now, it's all good.

 

Never thought of doing this as part of checking and cleaning - thanks.