Ok this is kinda hard to explain, but I will try because I am stumped.

About a week ago I got in my truck to go to work and turned the key and nothing happened. all lights seemed to work accept the dash/gauge lights. when I tried to start her nothing happened not click or anything. I cycled the key on and offa few time and then the dash lights came on and she turned over a couple time (more than usual) and started up. Next few times everything seemed normal. Then the next time she acted up I turned the key on and nothing so I left it on and after about 2 minutes I heared a click and lights came on and she started right up. But in the last time I noticed something wierd when she wouldnt start when I would depress the brake pedal the interior lights would dim.

So I went to the local parts store to get them to chack the elictrical system, they said battery was a little weak but ok, and the starter was ok. then they checked the alternator and said it is putting out the right voltage (14+/-) but the amperage was only 62.
He went and checked the computer and said it was supposed to be 120 amp. However in my research I have found that alternators for the 3.9 range from 75 amp to 120 amp and I am honestly not sure what the one in it is rated for because there are no markings left on it.

So anyway anyone experienced this or have any ideas. I have priced a new 120 amp alt. and they range from $60 (auto zone) to $200 (advance auto) But even the lower priced one is kinda out of budget right this moment.

If you need any more info I will try to provide it.

Thanks for all the info up front.

 

I know you said the store checked your battery, but the problem sounds to me like it is a bad terminal connection to your battery. I would try cleaning both the positive and negative terminal, and if there is a lot of corrosion, I would replace the terminals. The other possibility would be that you have a broken or bad gound connection to the engine block.

 

It's gotta be a loose connection somewhere

 

sorry, didn't finish. I agree check battery connections for corrosion and also that engine ground

 

Really does sound like a bad connection somewhere.

When you're checking your battery connections, pull on the cables at the battery terminal clamps too. I have found a few that had corroded inside of the clamps to where you could pull the cable out of them.

Check the engine side of the ground cable also. I have seen those go bad also. To look at it, everything looks ok but the cable was just "sitting there" and not really connected to the engine.

 

my question is what kind of amperage is your battery pushing??if its not enough your problem can still be battery related

 

mine did the same thing last week. I replaced the battery connections and ground wires, but it still did it. so I baught a new battery for it and it started right up. I think my old one had a dead cell or something.cause everything else would work except for the starter.