no, i didn't get it checked. when the gauge fall to 12, i assumed that 12 was coming from the batt, and figured it was fine. all the connections look good, except for the terminals are kinda beat up. i'm going to take the battery for a test and buy new terminals right now. i'll be back with the results in an hour. thankyou friend
You wouldn't get 12 from batt I get 9 10 but are you sure it isn't the belt when it drops raise the RPMs of it rises belts loose wet or old
breaker, i have seen this problem before. having a large chain auto store check your alternator is great but when you have a problem like this there machine cant always pick-up these types of issues, their machine is a little basic and sometimes you need to run them under a heavier load then they can do. if you have a specialty shop around you that specializes in alternator and started rebuilding that would be the place to go. many times the diodes are week and fail intermittently. wait long enough and it will fail permanently. this is more common then you would think. and if you are having a PCM issues that may need to be address as well although they don't usually mimic this problem. NOTE i said NOT USUALLY.
hope this helps
I had this same problem.Took a dip in some very deep,very muddy water,a few weeks later i was getting the intermittent no charge that you're describing.the alternator tested ok but ended up being the problem. the brushes were gummed up with dirt and was tearing itself up.
I still think it's a ground strap, maybe just a loose/rusty connection. Make sure that you have braided straps from the engine to the firewall, from the firewall to the (-) battery connection and from the starter to the (-) battery post (that one is a black 6-guage battery cable). Make sure the stud on the firewall is welded tight and does not turn at all, and that all ground connections are clean and tight.
If there is any doubt about this, run a seperate 6g black wire from the alternator case directly to the battery (-) post. Your problems appear to be alternator related, so it's suspect.
Years ago I replaced the stock 6g black and red battery wiring with 4g wires. But that's not required, I just did it as part of a dual battery upgrade.
1967 Kaiser Commando
2001 Grand Cherokee WJ
2003 Wrangler Rubicon TJ
hey all. i disconnected every ground and cleaned them all with a wire brush. the braided straps where they meet the firewall and the engine block, the 6 gauge wires at the battery and engine block and body. i attached the loose braided ground strap to the hood for good measure, even tho i'm not sure it ever went there. i removed the pcm and scratched up the places where it mounts, in case it acts as a ground. i could see that someone had done that before as well. a local old timer over here suggested an extra ground on the mounting blot of the pcm, so i did that as well. its a length of bailing wire from the pcm mounting bolt to the body. so far so good, no additional problems.