Hi,My wifes 2009 1.6 diesel focus died on her last night whilst driving. I am 99% sure its alternator as have checked battery voltage etc. I even put a known good battery on and got same results. It starts when charged but quickly drops from 12.6 volts. There is no rise in voltage whatsoever from the 12.6 it just drains down and dies. The alternator or wires or fuses must be the root cause. The wires seem tight and intact but given theres no voltage rise whatsoever im wondering if there is a fuse or fusable link. I dont have handbook or manual and not having joy with online searches for this year model.Dont want to buy alternator before ruling these fuses out. Can anyone possibly advise if there are any ?    

There are references to fuseable link in some focuses, but ive no concrete evidence to that, most posts I found say in the wire between alternator and battery. So id just check the continuity of the wires between alterantor and ground, and alternator and battery, and if they have continuity id say they are ok.

measure the voltage between alternator + and the alternator -, then you'll know if its the alternator?

No fuses that are changeable inside the alternator - although you may find you can switch out the regulator pack, which is a lot cheaper than a full alternator and most likely the culprit. Can often be changed on car too without removing the alternator.

the regulator will be something like this:

https://www.ebay.co.uk/itm/Alternator-Voltage-Regulator-fits-Ford-C-Max-Fiesta-Focus-Fusion-12-VOLT/123599078079?fits=Model%3AFocus|Cars+Year%3A2009&hash=item1cc71442bf:g:kkMAAOSwJp1cQHZk

or this:

https://www.ebay.co.uk/itm/ALTERNATOR-VOLTAGE-REGULATOR-FOR-FORD-KA-Fiesta-Focus-Fusion-Mazda-2/123602295145?fits=Model%3AFocus|Cars+Year%3A2009&hash=item1cc7455969:g:-4oAAOSwGq5cQwzL

or this:

https://www.ebay.co.uk/itm/New-Genuine-HELLA-Alternator-Regulator-5DR-009-728-341-Top-German-Quality/193137135589?fits=Model%3AFocus|Cars+Year%3A2009&hash=item2cf7decfe5:g:t34AAOSwAaJaFJIP

but you'll need to find the alternator and regulator parts numbers to check which you need.

If you find all the numbers, lots of the eBay sellers are helpful and will select the right one for you if you send them the info.