truck clicks as it is turning over but wont start,thinking at least one battery is dead,slow charge batteries all day,start the truck,both batteries reading only 12.2 volts with digital fluke meter.ok,alternator must not be charging correctly,remove alternator,carry it to auto zone and it is charging as it should.my question is.......is there a large fuse under the hood for the charging system that i am not seeing or is the alternator fine until it gets hot and then will not put out as it should ? anyone have any past problems such as this or have any input on possible solution? any help would be greatly appreciated. Clarkw123,...ProStreet65Ford,...Asphalt Assassin !!!

 

Did u take the batteries and have them load tested as well at the parts store? A lot of times batts will read fine with volt meter but when strained by the load of the engine cranking it kills them. I would start there if u have not already.

Are u getting a battery light at all when running? If u turn the key on with engine off, it should illuminate for a bulb check. Ford alternators have a 2 speed charging circuit. A lot of times the parts stores can only check the low speed circuit. At idle if should put out roughly 14 volts and the same at highway speed.