Ford Galaxy - Battery Junction Box / Auxiliary Fuse Box Repair and Replacement

[SilverBeast]

One of the common failures on the MKII Galaxy is overheating in the Battery Junction Box / Auxiliary Fuse Box located at the front of the engine bay under the Battery Cover.  This is caused by the inadequate crimps on the terminals fitted to the high current leads that are bolted into the box.  This causes a higher resistance than it was designed for.  The lead that takes the most current is the top one in the photo below which takes the charge current from the alternator to the battery via the 150 Amp fuse at the top of this box.  First symptoms will be warming of the terminal and wires.  If left unrepaired this will lead to overheating of the Auxiliary Fuse Box causing melting and eventual failure as in the shot below.

[attachimg=1]

First remove the Battery cover by undoing the two plastic fasteners
[attachimg=2]

and sliding forwards from the locating lugs at the rear
[attachimg=3]

Now the battery is exposed
Disconnect both battery terminals negative one first
Disconnect the red lead from the battery positive connection. (In this shot the battery has  been removed for safety and as I also treated the corrosion on the Battery Tray at the same time.
[attachimg=4]

In my case as the Battery Junction Box was damaged I sourced a replacement along with the top lead that runs to the alternator.
The multiplug and high current wires can be disconnected by undoing the nuts attached to the crimp terminals.  Take note of the order.
[attachimg=5]

The Battery Junction Box can be removed by depressing the lug at the tip of the screwdriver.
[attachimg=6]

and sliding to the right
[attachimg=7]

Here is my original and the replacement BJB
[attachimg=8]

The BJB can be split if desired, in order to clean up the terminals my removing the nuts on the Battery side of the BJB.
The fuse links can then be removed - taking care to keep them in order for refitting later - and releasing the clips that hold the two halves together.
[attachimg=9]

In order to prevent future failures it is best to solder the terminals.
I used a blowtorch with a soldering bit attachment to do this.
[attachimg=10]
Close up
[attachimg=11]

Here's the refitted Junction Box with soldered connections
[attachimg=12]

And a close up
[attachimg=13]

Things to note:-
(i) Different models have different numbers of connections.  Take note of the fuse link values (they are marked on the links)
(ii) If you source a second hand replacement then you can transfer the links from your old BJB to the new one
(iii) Clean the links lightly with emery paper/wire wool to remove any corrosion and do NOT use any grease as this will give a poor connection.
(iv) Crimp terminals can be replaced if the wiring is badly damaged.  The wire will need cutting back to where it has not been damaged by the heat (clean copper not black oxidised) or the failure may reoccur.  You probably won't be able to solder to heat damaged  copper anyway.
(v) If cable damage is too bad then a section of the cable may need cutting back and replacing (150Amp Welding cable is flexible and has the correct capacity for the Alternator link).  A "butt joint" crimp connector should be used and soldered.  Take care to adequately insulate the connection to prevent fire hazard and potential problems.

Question? Something not quite make sense?
Posts in the reference library are locked but you can start a new topic on the subject by clicking here