ford transit diesel 2002 2.4

[no1son]

Anyone suggest a possible remedy for my transit.Ignition warning light is on constant since changing battery 2 months ago,it is charging at 14 volts at high revs under full load and 12.7 volts under no load,therefore eliminating the alternator and voltage regulator.Belts are not loose nor is the starter connection and no cables showing signs of corrosion.The second problem I have is one of overheating when going uphill(the slightest incline).I have to drop speed to 45 for temperature gauge to resume normal temp.Vehicle is not losing water or oil.Is it possible these 2 faults are connected.Some transits have a 2 speed elec fan biting in at high speed but not this one it is fixed speed.(The temp problem appears wether I have a load on the back or not)I dont go above 70 and the gauge stays normal until I hit an incline.Appreciate any views.