hey everyone, im in desperate need of help on finding out what is going on with my truck. Friday my truck wouldnt start, luckily i was at oreilys, and they brought their tester out, and they tested it, the tester came back as dioelectrode in alternator bad, so being in a hurry to get my truck running, i went to the local salvage yard and grabbed an alternator off an identical truck of mine.(2008 dodge ram 1500 4.7l. 4wd), i swapped the two. jumped my truck again, drove all night, all seemed fine. well this morning i woke up, went outside to start my truck.....dead....so i jumped it...and so i thought i would go to oreilys to have them test my battery, and well my truck died on the highway while im driving...i had it towed back to my house. and i jumped my truck again...let it run a good 5mins, then unhooked the positve terminal on my battery to see if perhaps got a bad alternator from the salvage yard...well even after unhooking the postive terminal, my truck still running...and for a good 10-15 mins..so that tells me i dont have a bad alternator...right????....im running out of options of what to do..and i need to get my truck fixed asap. its my wife and i's only way of transportation....what else am i missing...ive checked my grounds...their good..my battery terminals are good...pcm???.......please help..all suggestion will be taken in.
thanks

 

You could have a battery draw, draining the battery over night. There is a test for that. I would reccommend NOT pulling the battery terminals off when running, that was the old school way. You can cause a volatge spike a fry PCM or other things.