Battery light indicator


#1

'99 Ford Exp. 5.4L 4x4 4 month old alternator. Battery light goes on and off.Seems to go on when I accelerate or when engine is hot.No drop in power when turn on lights/radio/AC.Tested voltage across battery/alternator and all ok.What is going on?


#2

Check the serpentine belt and belt tensioner.


#3

Most auto part stores will check your charging system and battery for free. Most of the time they do a good (not great) job and find the most common problems.


#4

I replaced the serpentine belt the other day but the light came back on. How do I check the tensioner? I also had the battery /alternator checked at two places and the readings were fine. Any other suggestion?


#5

Already changed but light still comes on. How do you check the tensioner is set to proper tension? I have noted the light to come on when the engine is accelerating and usually goes out when the strain on the engine is gone(which is why I suspected the s-belt). The light will also stay on when the engine has been going for awhile(more then an hour). There does not seem to be a drain on the battery, but I also do not want to leave my wife stranded in the middle of the night. HELP


#6

Bad diode in new alternator. go back and get another.
hopefully still under warranty???


#7

Had new alternator placed about four or five months ago. Will the voltage across the alternator show a drop because of a bad diode? If not, is there a way of testing the diode? Greatly appreciate your insight.