1994 W124 - Electrical??

[iamamanc]

Hi
I've not been here for a while but.....................
I have left the 1994 300d (W124) alone over the winter.
About 3 weeks ago I had to jump it to a start due to a flat battery and drove it about 5 miles. Got it back home and discovered that the battery would not hold a charge.
Yesterday I tried to jump it again. All the lights lit up and the glowplug light went out as it should but when I turned the key there was a loudish click and everything went dead as if I had blown a fuse. I checked the fuse box but couldn't see any blown fuses. I thought blown fuse because everything seemed a little damp due to the lack of activity.
Question:
Is there a main fuse that could have blown upon starting - if so where would it be?
Could the absolutely dead battery stop any activity at all when using jump leads so that it appears a fuse has blown
Cheers
Adrian

 

[Ted]

Sounds more like a dodgy connection on the jump leads.
Put a test light across the battery terminals. If it lights up you need to look further (OVP relay perhaps?)
If it doesn't, check the jump lead connections.

 

[grober]

You will have to buy a new battery anyway so this would be my first action- replace the existing one. 100Ah Varta or Bosch This will give a good basis/ power source for checking the battery leads/earth straps etc and further fault finding. You may find the problem is solved by this alone. Only thing to watch out for is a large power drain when you first connect the new battery indicating a large short to earth somewhere in the wiring. First suspect would be the alternator rectifier pack.