I have a 2004 F150 XLT 5.4 Triton, my alternator went out and my truck ran until battery died, I replaced alternator with new not reman, I have charged the battery to full, approximately 5 minutes after I start the truck the battery light comes on and stays on, have had both battery and new alternator tested, both check good, any ideas?

Thanks in advance

 

If all of that is true (good batt and alt), then you must have bad connections somewhere.

if you had alt prof installed then I’d go back to them with the issue and see why they say.

 

Make sure your battery connections are clean and the battery is fully charged then check you battery voltage (requires meter) while the truck is running. It should be greater than 14 volts. Report back with results.

 

Our trucks are very picky about the voltage regulator in aftermarket alts. I would replace with a motorcraft re-man alt.

 

Was the light on before you replaced the alternator?