ok my battery light is non stop flashing. all the lights in my truck are flashing, the battery gauge goes up and down, headlights flash, got a new battery and didnt fix anything, they said my alternator is fine. noone seems to know what is wrong. please help 2001 F150 4.6

 

I would investigate all grounding points and ground straps. Then I would disconnect and reconnect every wire harness I can get my hands on.

 

Could you be a little more specific regarding what you mean by flashing?
Do the lights go completely out then come back on, or do they just go somewhat dim and bright? Who checked the charging system and do you know how they determined the alternator was OK ?

 

The lights never go completely out it just looks like a disco in my truck, went around moving some wires around and now it is only doing it when I'm at a stop.

 

I am guessing you have an intermittent short in the very wires you moved around. Look for bad insulation, signs of chafing and stuff like that.

 

Some alternators are controlled by the PCM. It does sound like there is a voltage regulation control problem causing the varying voltage to the system.This could be caused by as bluewind stated poor connections or the alternator itself or the PCM if it is PCM controlled. That was why I questioned how it was determined the alt was OK because it can still charge allright, but with varying voltage the lights will show this.

 

Thank you both !