Ford fiesta mk7 battery warning light

[Craig1994]

Hi all really hoping for some help! 

 

2013 ford fiesta mk7 1.5 diesel 

Two weeks ago I have the battery warning light come on. Took the car to the garage and they found the altonator was bad. I had the altonator changed and for 3 days it was fine until the weekend started the car and after 30 seconds the battery light came on again. 

 

Took it back to the garage and had another altonator fitted and same again battery light still on. The altonator is charging but then dipps out goes from 11volts at idle and then up to near 14 volts when revs are on. 

3 altonators and all the same if the smart charge is plugged in or out this is still the same. 

 

Then recently I had low oil pressure warning come on I had the pressure switch changed 5 months ago and it's been fine till now. Garage confirmed the oil pressure is fine. 

 

So what could be causing this issue is the main wiring from the altonator also on the same loom as the oil pressure switch wiring. The oil light goes out on the dash

Has anyone come across this issue really need some help advice. 

 

Thanks in advance