Ok guys I'm back. Here's my problem. I have power to the whole truck until I turn something on, then I loose all power till turned back off. It started out as the truck would start run and drive until I turned the headlights/ running lights on then that would kill the truck. But that went away on its own. It did the same thing last night but after it died nothing would turn on. The cigarette lighter works fine turn ignition or acc on and it cuts out too.
I've checked my grounds and they all seem fine even cleaned em up just to be safe. Battery terminals are clean and tight. Battery says 14.? Volts to 15.? Volts. I'm stumped here guys. Any ideas???

 

You need to turn something on till it dies, and leave that something on, make it stay dead all the time. While it's dead, do your voltage checks out at the solenoid area where all the power comes from.

 

Yes, the only way that can happen is if something up by the battery and its connections to power distribution wires is amiss.

14.x - 15V from a battery without the engine running is kind of high if you ask me, I'd expect 11.x - 12.x.

 

Still sounds like a ground problem

 

ok thanks guys. I did take my battery in to get it tested tonight which it failed horribly! So I got a new one and so far the problems gone except now while its running its only crankin out 11.72ish volts. Could this be the voltage regulator? Wouldn't the alternator just go out completely?

 

Sounds like the alternator did go out completely, 11.72 is only the battery. Take the alternator off, take it in and have it tested on their machine. If you want to test it yourself, take the wire off the "F" terminal and tape it. Take a scrap piece of wire and hook it to the "F" terminal on the alternator, and lay it up beside the battery. Start the engine and put your meter leads on the battery, and while doing this, touch the "F" wire to the + of the battery. If the voltage on the battery jumps up, then the alternator is good.

 

You're out in the cold with a flashlight. Light gets dim and goes out. Few minutes later you switch it on and have light for a couple minutes. Same idea with the battery.

Less than 12 volts means you're running the truck off of the battery. It's now running off of non-renewable batteries like a flashlight. Based on the amperage of the battery it could be less than a day before you're back in last night's shoes.

The battery basically provides the starting voltage and a buffer between the electronics and the alternator. BEfore computers came into play a simple alternator test was to remove the battery with the engine running. Think about the old days when cars had a hand crank and a generator.

I always just replace the whole alt, but I'm used to dealing with high mileage cars. You can take the alt in and have it and the voltage regulator load tested. But, you need to do one of those before you end up buying another battery. Think about this- auto battery tenders are trickle charge, not deep cycle.

 

This may be true, I'm not old enough to remember so far back, and I thought you were, like, 21 yo or somewhere thereabouts?

No, don't think about the old days with hand-crank starters and generators (which were 6V and I believe positive-ground systems)....

I won't even suggest doing this as a test, even on something as antique as a 1980s vintage as I've read tooooo many stories here from guys who destroy their charging systems this way - "My headlights got real bright and burned out and some wires started smoking when I stepped on the gas, this happened twice, why did this happen?"

You'd probably be surprised at some of the stoopid chit that some guys do.

I am also big on providing verifiable information from credible & authoritative sources, not merely backyard hacks learned from a dead uncle three-times removed but presented as fact, I hate that and will ask people to cite their sources when I see wild claims being posted like that.

Anyhow, about disconnecting the battery from a running vehicle and why that's a bad idea:

Alternator Field Disconnect

 

I'm takin the alt. In today to see if its good or bad. Today drivin to work the volt gage in the truck was sayin just under the half mark with out lights on with lights it would say damn near dead. Drive with the lights on they get really dim, turn em off for a few and they're bright again and slowly go dim. But I'm deff gettin the alt tested.

 

If you're referring to a factory gauge, it's an ammeter and not a voltmeter....

 

Ok alternator tested bad too.. This is like the 3rd alternator and 2nd battery in less than a year! What could be causing them to fail this fast?

 

And my bad that would explain a lil bit. I've been thinkin its volts not amps.

 

Yep, 21.

And yes, before anyone turns their truck into 10,000 soda cans, listen to ctubutis. I forget that I've seen "port/polish" with a dremel, and an electric leaf blower on an intake.

The point I was trying to make, poorly I guess, was that your running voltage should be coming from the alt not the battery. That's why in ~40yo diesel sedans you see 70 or 80 amp alternators. Shopping for a modern car you can see 140 or 150 amp alts. Here's a quick summary of how bad alternators can give false ammeter ratings:Voltmeter vs. Ammeter - Auto Meter Tech Tips: And here's a good rundown of a charging system.Automotive Charging Systems - A Short Course on How They Work

And I've done the battery removed test on a couple cars. Trying to diagnose a '58 suburban I bought out of a field frustrated and at night. Nothing on but the motor. In a car built in the last 40+ years the trouble is that electrical surge will find the path of least resistance and blow, just like a storm surge in a house.

I'd just had hernia surgery so I had to have a local auto store put in a battery in a 95 BMW, it was 75lbs and under the rear seat. The kid tightened the battery bracket backwards, so it wasn't holding anything down. I hit a bad pothole, the negative cable came off, blew the strip fuses under the rear seat and the brake lights. Sparks burnt a hole in the seam foam. The engine kept running hah, but yes only take a battery out if you're making a DIY cash 4 clunkers.

 

I think there is some stuff in the sticky about diagnosing the charging system, and grubbworm has some stuff in his albums or galleries that might help.

Have you put a voltmeter on the battery with the engine running?

 

Last night that's where the 11.72ish came from but I haven't yet today. And ill check out his stuff see if any helps me out thanks!