[rayford]

I know the alternator has been kicked around a lot on here already but I have a strange situation..my alternator went out so I got one from a yard in CT. it seemed good and even said remanufactured on a sticker, and it did work good for about 300 miles, then the warning lights came on. so I had about 30 miles to go , I turned off everything that I could such as the a/c, radio and even the lights as it wasn't near dark yet. well after about 9 miles the lights all went out so I figured it might have just been burshes not seated good but the next day after a few miles the lights came on again. This time I put the old alternator back on and it worked fine. I checked with a volt ohm meter with the ground lead on the neg. post and the the red lead to the positive post and it checked good ,, it did vary with speed of engine and accessories but was above 12.7 at the lowest and was up in the 14's at the highest. Well I though I would put the one back on that I got recently and stopped working just to check the voltage on it.. and it tested about the same but I drove it only about 4 miles and all the lights came on again so I came home and checked it.. it was still showing good voltage readings but the warning lights were still on. I put the old alternator back on . and it checked the same as the one that made the lights come on but with the old one installed the lights stay off... does anyone know why this is happening?? it is just curious to me??? thanks. Vernon