The oil pressure has to be measured with a mechanical gauge.
If it shows normal then just replace the oil pressure switch but If it is showing abnormal then it mean that either the oil pump needs to changed or the engine bearings.
Remove the overhead control panel control module and Pull inside the rear view mirror down at one side
FYI The inside rear view mirror is held by spring tension
Now disconnect connector from overhead control panel control module and remove inside rear view mirror.
For installation do the same thing in reverse order.
Read the car requirement and im sure it wont be more than 95 Octane, which is special fuel here (cheaper one). usually minmum requirement is 92 octane 9i guess).
Super is 98 octane only preffered if you want an inch more of performance while burning fuel like few more HP, better acceleration etc.
usually battery fuse is very next to battery and its the MAX AMP (biggest AMP like 60-90 AMP).
And yes it could be the cause of non charging, While fixing that, look at electrical short circuit whay it has happened. Otherwise battery fuses are very strong and bomb proof. Some major short circuit cause them melt.
Alternator has no life. It may work for 10 years too and it may end up crashing within 2 years. Its very hard to put figure on such electrical part. But usually it stays long enough unless not spoiled with water or any other short circuits.
i just bought a 4th hand Merc A class which i had got it checked before buying and just after a week all the lights on the display panel went on but no problem with the car
was i cheated or its just the display panel needs a change.
thanks