I have a 1999 Ford F-250 with a 7.3 diesel. My batteries will not hold a charge. I just replaced my alternator, battery cables and cylenoid (sp.


Asked by Dec 17, 2013 at 10:56 PM about the 1999 Ford F-250 Super Duty Lariat 4WD Extended Cab LB

Question type: Maintenance & Repair

Does anyone have any idea why this is happening?

3 Answers


Most chances one of your two batteries is bad. If one is bad it will kill the other one. Did you disconnect both of them and test them independently of each other?


No i didn't test them independently. If that is the problem that would cause the alternator not charge the batteries? When I replaced the alternator I charged the batteries last night and started my truck and let it run for about 10 minutes I turned the headlights on and the blower motor the longer the both were on the amps would just keep dropping? I appreciate any other help.

1 of 1 people found this helpful.

I tested the batteries and you were right one was bad and the other wasn't in the greatest shape as well. So I replaced them both. When the motor is running and there is no load on it, the alternator is charging only 12.2 volts, and when there is a load on it the volts go down to 11.6-11.7 which it would always charge at 14.2-14.4. Any thoughts are appreciated..Thanks a bunch..

Your Answer

F-250 Super Duty

Looking for a Used F-250 Super Duty in your area?

CarGurus has 44,905 nationwide F-250 Super Duty listings starting at $1,600.


Ford F-250 Super Duty Experts

  • #1
    Tracy Hooks
  • #2
    Tom Demyan
  • #3
    David Gray
View All

Related Models For Sale

Used Ford F-350 Super Duty
417 Great Deals out of 25,533 listings starting at $3,900
Used Ford F-150
2,558 Great Deals out of 220,223 listings starting at $1,222
Used Dodge Ram 2500
155 Great Deals out of 5,015 listings starting at $3,250
Used Ford F-250
417 listings starting at $3,500
Used Chevrolet Silverado 1500
2,199 Great Deals out of 151,084 listings starting at $1,499
Used Ford F-450 Super Duty
34 Great Deals out of 2,472 listings starting at $9,995
Used GMC Sierra 1500
887 Great Deals out of 59,331 listings starting at $1,980
Used Toyota Tundra
566 Great Deals out of 37,256 listings starting at $1,500
Used Dodge Ram 3500
93 Great Deals out of 2,220 listings starting at $5,950

Used Cars For Sale

2018 Ford F-250 Super Duty For Sale
16,607 listings starting at $24,634
2017 Ford F-250 Super Duty For Sale
13 Great Deals out of 11,172 listings starting at $17,465
2016 Ford F-250 Super Duty For Sale
18 Great Deals out of 2,347 listings starting at $19,788
2015 Ford F-250 Super Duty For Sale
35 Great Deals out of 2,419 listings starting at $14,424
2014 Ford F-250 Super Duty For Sale
11 Great Deals out of 1,124 listings starting at $9,975

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.