So where's the fuse??? - The Unofficial BMW M5 Messageboard (m5board.com)

London Mike · 16th September 2006, 21:52

OK, while messing around doing the wiring in the main electrics box in the engine compartment, the one with the DME in, the main red power feed on the little post managed to get touched to earth and blew the fuse. The question is where IS the fuse, we can't find it anywhere...

If you look at the battery there are 3 main power leads coming off the + terminal. One is the main one, another smaller one goes across behind the battery and runs up the side of the tunnel, this one has a black box with a big fused link which is intact, it isn't that one. It's the one that runs down with the main power lead just inside the right hand sill. We can't see a fuse either at the battery end or in the front footwell where it emerges before going up into the electrics box

Anyone had a look with the carpets out and know where the fuse is? We have no power to the post in the electrics box anymore and we've run out of places to look. I'm loathe to rip out all the carpet to trace the whole length, I can't see why they'd fuse it there as it could be so easily done next to the battery...

London Mike · 18th September 2006, 01:16

NOBODY knows???

AliveM5 · 18th September 2006, 09:52

Was there much of a "bang" when you shorted out the post to earth ? maybe the wire itself has melted somewhere along its length.

London Mike · 18th September 2006, 11:03

Nope, it was a quick contact with no real 'bang' and the wire is about 10mm thick so it hasn't melted for sure

yewcorner · 18th September 2006, 11:25

Mike,

I've had the carpet up before as I was looking at why one of speakers was 'whining'. I don't remember seeing any fuses?

Quote:

Originally Posted by London Mike

NOBODY knows???

tadpole · 18th September 2006, 11:54

Have you checked under the near side rear seat. There are some fuses, some of which are under a cover you have to unscrew. I have not got the car otherwise I would have a check for you.
Phil..

London Mike · 18th September 2006, 12:01

Quote:

Originally Posted by tadpole

Have you checked under the near side rear seat. There are some fuses, some of which are under a cover you have to unscrew. I have not got the car otherwise I would have a check for you.
Phil..

It's not in there, that are all the fuses for central locking and similar, the power lines are on the right hand side

madm5 · 18th September 2006, 14:33

Do you mean the + connector under the bonnet for jump starting? If so i think the red wire goes straight to the alternator with no fuse.

unesential · 18th September 2006, 15:13

There is no fuse listed. Wire should run direct to Under bonnet terminal post. From there back to the battery. Terminal in DME box for bus to DME, Airpump, and Fuel Pump relay. Back to B+ terminal then to battery. Fused wire from battery goes to power distribution.

The Bigfella · 18th September 2006, 15:16

This is sounding like you have a session with a multimeter and some jumper leads coming up. You have my sympathies - I just rewired the genset engine on my boat.

Ian

London Mike · 18th September 2006, 16:49

Quote:

Originally Posted by unesential

There is no fuse listed. Wire should run direct to Under bonnet terminal post. From there back to the battery. Terminal in DME box for bus to DME, Airpump, and Fuel Pump relay. Back to B+ terminal then to battery. Fused wire from battery goes to power distribution.

And this is what is worrying me, that's how I understood it too. But we have no power at the terminal so something's wrong. Yup, a long session with a meter looks like the way forward here. Oh goody...

unesential · 18th September 2006, 19:57

Check for power at the B+ post. If you are good there then it is cable to DME bus. If not my sympathies.

London Mike · 21st September 2006, 10:46

It has an in-line fused link that is underneath the rubber sheathing. You have to pull the cable through from the battery compartment into the rear footwell then peel back the rubber to get to it. I cut it our and replaced it with a proper large 50 fuse which is now mounted next to the battery