Battery Light On, lights flicker

[GotDiesel85]

2000 F250 7.3

Ok, at low speades low rpm my battery light comes on and my lights dim and brighten. this tells me maybe an alternator problem. So i tested it and the batteries. Both batts and the alternator are fine. No DTCs, Any suggestions?

[VolTone]

I had an altenator that tested out OK and charging but just wasn't charging strong enough. Sounds like you could have a similar problem. Did you test or automotive store?

[forddieseldoctor]

Is your charging voltage steady or bouncing up and down? I've seen this before and I found a corroded splice where the orange and light blue wire meets the large black and orange wire. If you take and run a fused jumper from the positive battery terminal and backprobe it into the orange and light blue wire with it running and see if the headlamps stop flickering. If the stop than you need to trace the orange and light blue wire and see if you can find the bad spot.

[Roc87]

Both times my Batt light has been on, the volt gauge doesn't move at all, yet the gauge on the bully dog GT showed the volts dropping to 12.2. Did you take the alternator off to have them test it? If it is the alternator going bad, do yourself a favor and get a NEW ONE, not a rebuild, my last rebuild lasted 2 months. A rebuild is only good as a spare under the seat

[GotDiesel85]

my voltage guage is stayin at around 14 constant. I traced the wires back and they look fine. so i just flat out replaced them and it solved my problem. Thanks for help guys.

[GotDiesel85]

And i tested it at work. then had it checked at napa. It was rebuilt it was brand new. had for three months

[ltfire344]

hey i'm having the same problem on my '02 f-250. What did you end up replacing?

[dereku]

I had that issues I had 2 bad alternators.

[GotDiesel85]

Originally Posted by ltfire344

hey i'm having the same problem on my '02 f-250. What did you end up replacing?

back trace the battery cable to an orange and light blue wire. i replace my positive cable and the orange and light blue. made sure the cables where good and tight and my problem is no longer there. my pickup is a single alternator setup and it is brand new and opperating perfectly. replacing one was expensive enough, i hate to see two.

[GotDiesel85]

i think somebody had replaced it before cuz its suppose to be black and orange.