Fired the truck up this mornin and the battery light came on on tha dash and could smell a burnt electrical smell.Got the volt meter out and checked voltage and sure enough 11.97 volts while running and 11.97 with engine reved up to 2500 rpms.High output alternator bad @ 49000 mile's (bummer).Now i know what my issue a couple of weeks ago was when i had a low moaning noise under the hood was.Alternator going bad and loading the motor up causing the noise.250.00 for a new one. Anyone know an easy way to change them out?Looks like through the inner fender is the easiest. Thanks

 

just curious, my alternator went in my 08 f250, ford wants 650.00 for a new one, I would like to get an after market one for half the price, the guy at ford said make sure its PCM controlled, I havent found any mention of a PCM controlled alt, neither did the mechanic selling me the aftermarket one, is ford toying with me

 

Yes the PCM controls the charging rate of the alt, if the PCM doesn't see the correct voltage, it then sends signal to Instrument cluster and the battery light is illuminated.

Are you sure the alternator is bad. There are two fusible links that should be checked for power on the passenger side of the truck, if one or both the fusible links is bad, you need to figure out what caused them to fail, then they need to be replaced followed by a recheck of the charging system.

If you have power to the fusible links you should check the batteries with a load tester. If the batteries are weak or bad the alternator can get overloaded and the PCM will shut it down. Bad or weak batteries can cause a lot of issues on the 6.4. Always check the easy stuff before to change hard parts. Hope this helps.