1994 Ford F-150 battery keeps overcharging then dying

SARAH.SERVICE

MEMBER
1994 FORD F-150
6 CYL
4WD
AUTOMATIC
191,000 MILES

I put in a new starter about 2 weeks ago it seemed that everything was working fine. When I turned it on a couple days ago and touch the accelerator the battery guage went to max and the battery light came on. After driving it that way for about an hour I turned it off and waited about an hour then turned it back on and everything seemed normal drove about 10 miles and turned it off again about 6 hours later went to turn it on and the battery was dead. Jumped the truck and drove it off and on for the remainder of the day with no problems parked it for the night went to start it in the morning and the battery was dead again. Pulled the battery put it on the trickle charger overnight put it back in the truck and started the truck with no problem but the battery is saying by the guage that it is over charged again? What could be the problem? It seems like the energy is being pulled from something while the truck is turned off.

1 Reply

BILLYMAC

MECHANIC
2,204 POSTS

Hi billymac here. Well sounds like most likely you have a bad alternator or possibly a bad regulator. However with this paticular vehicle there is other things that have to be checked. If the batt is good and fully charged and runs completely down overnite you have a pretty good draw. And a draw like that will cause heat. So something will be hot in the morning. Before you start your truck raise the hood touch the alternator regulator and the a/c compressor. Put your hand on the steering coloumn the cruise control and the heater motor if any of these items are hot that will be where your draw is comeing from. If a mechanic was trying to repair this prob he would do a draw test to see exactly how many amps of draw their is. This requires some special tools. But if you turn truck off close all the doors make sure no lights are on. Disconnect the neg batt cable touch the cable briefly as in rub the cable end against the neg batt post you will see a spark a spark like from a lighter is normal. However one like jumper cables make is too much. Your chargeing system should never go beyond 14 volts. Since yours does this points directly to the charge system. I hope this helps. Billy mac