Loss Of Power, Faulty Electric Window And Central Locking

[gnv15]

Have a strange problem at the moment. Auto Vw Sharan 2005 1.9TDi, done 56000 miles. Last week suddenly lost power on motorway while going uphill. Serviced only 4 weeks ago. Its alright doing city rounds but on motorway struggles with anything uphill and cant reach 60. also at the same time, the front driver side electric window and central locking are not working. I saw somewhere in the forum that a faulty multiplug in the front door can cause electric and turbo problems. Before I change the MAF, could some one point me in the right direction please? If it is the multiplug, how can i change it? Any help is much appreciated