I have a 2000 F150, 5.4L. I had the radio cut out on me on the way home, didn’t think much of it at the time because for the last six months the display on the radio was out. Thought maybe it was just going. While driving home all of the gauges pegged out and then the entire dash went completely dead. No wipers, dash lights dome light etc… Thought it was the battery, still the original (8+ years). Received a jump start from a battery pack and things seemed to be back to normal until I got home. I turned the truck off and tried to restart it but again was unable to start the vehicle.
Figuring it was the battery I went down to Sears and bought a new 850 A replacement. This seemed to work for a couple days but on the way home from camping this weekend the voltage gauge was showing none if any voltage being registered. Turned things off in the cab and made it home without incident.
Again, I tried to start the truck but it wasn’t receiving enough to turn it over. I had AAA come with the battery truck and evaluate it but he said that the alternator appeared fine at the time he checked it out. Is it the alternator?, Battery bad? Or is something draining the battery? Any thoughts?

 

The first thing that you have to do is get the emgine started somehow, Then using a volt meter test the output of the alternator. You test the alternator by putting theprobe on the output terminal of the alternator and then ground the other probe. The reading should be some wher around 13.6 volts dc. If the reading is either way high or very low than the alternator /regulator is suspect(i am not sure if you have an external regulator).

 

Sounds like alternator to me.

 

+1

Phil

 

Check the connections at the starter. You are looking for corrosion in the wires. It is a known issue with the f-150. The dissimilar metals in the nut and stud on the battery wire going to the starter and the ground on the frame coming from the battery causes corrosion to wick up the wire under the plastic covering.

Regards

Jean Marc Chartier