99 B4000 electrical problem

[99B4000_4x4]

Im having a problem with my battery light blinking. It does it at start up, and then it will idle just fine with the battery light off. But once I rev the motor the light will blink on and off randomly. If revved at about 2500 rpm it stays on constantly. I checked the battery cables and they are actually corroded pretty good. Does that mean the cables are bad or that the alternator is going out? Or could the corroded cables caused the alternator to start going out? In which case both would need to be replaced. Any help would be appreciated. Thanks.

 

[Ship]

clean the cables and make sure you have a good connection .. once you have the truck running disconnect the ground from the batt .. if your truck stays running you alt is good .. if it dies out right away then its your alt for sure ..

dirty / corroded cables are really bad for the chaging system .. maybe not bad but makes it harder for the system to charge that batt .. and now the vehicle is releyin more on the alt then it would normaly if there was a good clean connection ..

also .. can make sure the belt is good .. pulley is tight on the alt .. and the connections at the alt are tight and clean

hope that helps ya

 

[99B4000_4x4]

I unhooked the negative battery cable today like you said, and sure enough the truck died. I have been looking at alternators online and I was wondering if there is a difference between one that is on an automatic or a manual transmission? Some websites act like alternators are different depending on the transmission. Mine is a manual. The pictures all look the same though. I was wondering if the pulley is different or something? Thanks for all the help.

 

[Ship]

I dont see why there would be a diffenece in the alternator from auto to std .. I used to rebuild alt's and starters .. and it was never an issue ..

 

[locknar]

I agree with Ship about the dirty/corroded cables, might as well check the connections BEFORE the purchase