W460/W461 3D Printed Fuse Block Replacement

izak

G-Wagen Club SA
Joined
Oct 19, 2021
Messages
22
Age
41
Location
Pretoria
Like most of the old Geländewagen owners I’ve been looking to replace my W461’s aging fuse block. The traditional torpedo-style ceramic fuses are delicate and have a short lifespan. Recently, my interior blower fan fuse burned out, causing the fuse block to melt - I need my aircon so it had to be fixed!

1710669469354.jpeg


Replacing it with another original fuse block was not an option - even if I could find one I would eventually end up with the same problems.

So, an upgrade was necessary, preferably to newer-style blade fuses. Initially, I hoped to find a drop-in replacement that could be used as is. However, upon mapping out the fuses with my multimeter, I noticed that the supply side of the fuses are bonded together. Another complication arose when I removed the fuse block and observed that the load side of the fuse block has two outputs on every circuit. Search as I might, I could not find anything that has this configuration.

I then stumbled upon a possible solution on Thingiverse - CGermann created a 3D printable model of a W460/W461 fuse block that looked like it might work.

A friend helped out with printing the fuse block in PLA and, after checking that it fitted as expected, I was ready to start the project.

The 3D printed fuse block has removable fuse holders which friction fit into slots on the fuse block. Two quick disconnect terminals are needed for every fuse block. The quick disconnect terminals need to have a retaining clip to ensure they stay snug in the fuse block. I ordered Würth terminals from Manntech that worked perfectly:

TERMINAL UN-INS BRASS 6.35mmx0.8 FEM
1710670255168.png

TERMINAL UN-INS BRASS 6.3mmx0.8 MALE
1710670270338.png



I used the quick disconnect terminals to bridge the supply side and added the one or two (where required) male connectors on the load side. Here is a picture of what a completed fuse holder looks like before heatshrinking:


1710669515650.jpeg


I used 1.5mm² automotive wire cut into ~80mm lengths to build up the connectors to match with the setup in the car. I found that length of wire to be the sweet spot - there was no stress on the wiring and it was easy to reach all the terminals I had to connect to. A good crimping tool will make things go a lot easier and keep the swear jar empty.

Use good quality heatshrink on the male terminals (or use insulated male terminals). I found that some of the female terminal connectors on the car had a very loose fit and I just tightened them up gently with my pliers.

These fuse block supply terminals were bonded on my car - yours might be different so just confirm on yours:
1-2 Bonded
3-4 Bonded
5-6 Bonded
7-8 Bonded
9 - Single
10,11,12 Bonded

In the end I was very happy with the outcome and I highly recommended it if you also have issues with your old fuse block.

I attach the 3D Printer STL files to this post with thanks to CGermann (just archiving it here should it disappear from Thingiverse).

There are three files:
The fuse block
The fuse holder
A tighter-fit fuse holder (might be needed for some printers). I started with this one and just took of a bit of material by sanding lightly to achieve the desired fit.


End result:
1710669571804.jpeg
 

Andrew

Well-Known Member
Joined
Oct 8, 2008
Messages
3,795
Location
Brits
This is a good upgrade Izak. It looks very well done. Thanks for these files. I might just copy you for my next build.

I am not sure what you used but the fuse that melted (F10) that controls the A/c interior fans should be 25A - with 2.5mm wire. (The non AC versions have a 7.5A fuse.)
The condensor fan up front uses a separate 16A fuse. I assume you have a factory AC.

From my 1987 wiring diagram:

F1 - 16A
F2 - F7 - 8A
F8 - F9 - 16 A
F10 - 25A (with AC)
F11 - 16A
F12 - 8A
Extra circuit F13 - 16A for condensor fan
 

izak

G-Wagen Club SA
Joined
Oct 19, 2021
Messages
22
Age
41
Location
Pretoria
Thanks Andrew, that looks almost similar to mine, but F10 is 16A according to a fuse printout I received with the G. The wire on F10 measures the same as the other 16A circuits... but then my 290GD is actually a M104 so not entirely sure what is stock and what is not :) from what you say I deduce it must be an aftermarket A/C then.
 
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