Urgent assistance- electrics -W124

[MB250TD]

If anyone can help before dark, I would be grateful! Car is W124 300TD. Problem following reinstalling a recharged battery. Nothing works - not even lights! I have noticed that the shorter lead from the positive battery terminal is not attached to anything, but I have not detached it! I cannot believe that a positive lead should be lying around unconnected. The lead is about 20cm long or so, and ends in an eye, as though a bolt should pass through it. I cannot see any relevant connection! The connections on top of the plastic unit sticking out from the suspension strut are all intact. Is this missing coinnection my problem and if so where does it go? Urgent help appreciated because I need to use the car to work tomorrow morning. battery definitely gives a good read out, and earth connections OK.
Many Thanks.

 

[MB250TD]

I should add car is a 1995 W124 300TD with 606 engine.
Thanks

 

[grober]

There are 2 leads from the positive terminal on my battery. One large about 12mm diameter covered in shiny black insulation, it vanishes into the bowels of the bulkhead. the second smaller lead covered in a matt black patterned insulation runs straight to the bolt connections on top of the black lidded rectangular plastic unit sticking out from the suspension strut. this appears to be a connector bus to feed to several powersupply leads -red in colour. This is major power supply to several key units. see picture smaller lead highlighted in green. Is this the lead you are referring to??

 

[MB250TD]

Thanks Graeme,
Thats the one! I have reconnected cable to terminal under the plastic cable and everything becomes live......except blower! I do not know why the blower is not working - got too dark now, so a problem for tomorrow evening..... I certainly did not undo the connection for this live feed to the car, and can only assume that it had been pushed in under the plastic cover against the bolt of the terminal, and never bolted in place. I needed a socket spanner to undo the bolt! I assume that when I removed the battery, it had pulled the cable adrift. seems oadd that anyone would have left it like that?
Anyway, thanks for your help and the useful photo.
If anyone has any idea about the blower (fuse OK), then let me know!!
John

 

[grober]

blower inline fuse

I believe the Blower has a separate fuse external to the fuse box. The picture" inlinefuse" shows the location of the fuse but the owner has replaced the 30amp strip type fuse with fused link with pink wires. The picture "fusething" gives an idea of what it should look like but its from an older mb model. Evidently if this fuse is blown it may indicate a problem with the blower motor-high current draw or they can develop a transverse hairline crack so short out briefly to test with a suitably large gauge wire. I should acknowledge the help of 2 posts from the mercedes shop forum for these pics.

 

[grober]

fuse mystery deepens!

Update I have looked for this fuse link unit in my own car and CANT FIND IT!! Maybe only for aircon cars or its locations been changed I dont know. I would guess that some sort of independent inline fuse for the blower exists but dont know . maybe someone else knows

 

[MB250TD]

Thanks Graeme for suggestion and useful pictures.
From memory, there are two in line fuses (25a) and (7.5a), latter within a rubber holder on wires between the terminal holder on the upper suspension strut (battery side of car) and the wires pass into the box under the fuse box on the offsiide of the car. I thought that these were to do with the Scorpion alarm. I am not sure if there are any similar fuse holders on offside outside of fuse box. I will look this evening. I suspect that blower would have a big fuse (30 a or so ?). The blower is only a year old and hence I do not expect problems with it. However it is frustrating that it does not work, and did before replacing the battery. It must be something simple like a fuse.
Regards
John

 

[MB250TD]

Problem solved. I found a loose plug connection to the heater element to the right of the fuse & relay box and up under windscreen under bonnet. Plugged in and all now works.
Many thanks for help and suggestions.
John