Hey, new to the forum and have a question about my f-250 (light duty). It all started about a week ago when the battery light on the dash began to flash every once in a while, the needle on the gauge stayed about 2/3 the way up. Got an alternator from the wrecker (tested out as good) and no change, cleaned all the connections and still no power from the alt. swapped it out with a known good alt. and good battery and still no change. Fuses are fine and i changed out the alternator harness from my 98 f-250 and still no charge coming from the alt. has anyone dealt with this type of mess? Thanks in advance.

 

Also swapped out the relay? On the firewall and no change. The alternator from the wrecker got put on the 98 f-250 and it works great 14.8 volts. Put a test light after to fusible link and into the two links and theres power there

 

Ok. Replaced the ends that plug back into the alternator and still no power coming from the alt. cleaned the grounds and ran a set of booster cables from the block to the chassis aswell as one from the body of the alt to the negative post on the battery and still nothing??? Any help would be appreciated.

 

Bonus. Have a spare alternator, belt and harness.

 

Well.. share the cause of all of this so we can know too...

 

Power was coming from the red/blue wire into the fuse which becomes the green/red wire that goes into the fire wall (connector under starter relay). Put a test light probe into the end of it and had to twist it to see power at that connector. Plugged it back into the harness and no power to the alt. Twisted the plug alittle got a quick blurp of power. Cut and spliced in a jumper and all was good. Going to the wrecker to get a proper wire and will cut it long so there is no more tension on that wire and connector.