FAQ: US vs Euro differences in electrical wiring / system and fuse boxes

E28 technical advice asked and given! Troubleshooting, modifications and more.
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cek
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FAQ: US vs Euro differences in electrical wiring / system and fuse boxes

Post by cek »

This FAQ covers "How do the electrical systems in US and Euro E28s differ?"

FAQ: How do the fuse boxes in US and Euro E28s differ?

There are two different fuse boxes for E28s:

For ALL US cars, and a few Euro (520i) cars:
Part Numbers:
61131369596 from 09/01/1980
Superseded by: 61131370763 (09/01/1982 — )
61131386387 (03/14/1997 — )
Supersedes:
61131364843 (12/01/1977 — )


Part 61131369596 was found on the following E28 vehicles:
5' E28, 520i, Sedan, M20, MANUAL, EUR, (4031) : Fuse box
5' E28, 520i, Sedan, M20, AUTO, EUR, (4041) : Fuse box
5' E28, 520i, Sedan, M20, MANUAL, EUR, (4051) : Fuse box
5' E28, 520i, Sedan, M20, MANUAL, EUR, (4052) : Fuse box
5' E28, 520i, Sedan, M20, AUTO, EUR, (4061) : Fuse box
5' E28, 520i, Sedan, M20, AUTO, EUR, (4062) : Fuse box
5' E28, 520i, Sedan, M20, MANUAL, EUR, (4071) : Fuse box
5' E28, 520i, Sedan, M20, MANUAL, EUR, (4072) : Fuse box
5' E28, 520i, Sedan, M20, AUTO, EUR, (4081) : Fuse box
5' E28, 520i, Sedan, M20, AUTO, EUR, (4082) : Fuse box
5' E28, 524td, Sedan, M21, MANUAL, USA, (4214) : Fuse box
5' E28, 524td, Sedan, M21, AUTO, USA, (4224) : Fuse box
5' E28, 528e, Sedan, M20, MANUAL, USA, (4073) : Fuse box
5' E28, 528e, Sedan, M20, AUTO, USA, (4083) : Fuse box
5' E28, 533i, Sedan, M30, MANUAL, USA, (4274) : Fuse box
5' E28, 533i, Sedan, M30, AUTO, USA, (4284) : Fuse box
5' E28, 535i, Sedan, M30, MANUAL, USA, (DC74) : Fuse box
5' E28, 535i, Sedan, M30, AUTO, USA, (DC84) : Fuse box
5' E28, M5, Sedan, S38, MANUAL, USA, (DC93) : Fuse box

Source: This thread on Fuse box part numbers: viewtopic.php?f=3&t=137107&p=1358165
US Cover:
Image

US Frontside:
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US Backside, unmolested, all wires:
Image

US Backside:
Image

Fuse 7 & 8 are fed by a WH/VI lead from the high-beam relay. This lead is built-into the fuse box and goes directly to the spade under fuse 7:
Image

Fuse 7 & 8 input-side are bridged. This is the easiest way to tell whether you have a US or Euro fusebox.

For all Euro cars, except 520i - Part #: 61131370426 (04/01/1981 -)

Euro Cover in English (UK):
Image

Euro Cover in German:
Image

Euro Frontside:
Image

Euro Backside with all wires:
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Euro Backside:
Image

Fuse 2 is low beam (right). Fuse 3 is low beam (left) + rear fog. Comes from output of low-beam relay (YL 2.5).

Fuse 7 & 8 have INDEPENDENT inputs. Fuse 7 comes from the output of the high-beam relay (WH/VI 2.5).

Note how Fuse 8 has the VI 2.5 lead going to it; it is a jumper from the input to Fuse 11.
Image

The Euro diagrams show this:
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Here's Fuse 7; on Euro cars Fuse 7 powers BOTH L & R High beams.
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Inside the fuse box, the lead comes out of the harness from the chassis into the fusebox, directly to Fuse 11, where it then jumpers to Fuse 8.
Image

Here's a pic that highlights the differences in the fuse boxes (US on left, Euro on right):
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Summary of connection/mechanical differences between the US and Euro Fuse Boxes

The only structural difference between the two units is: On the US version the input to Fuse 7 & 8 is bridged. On Euro versions the inputs are separate. Thus a European box can be made to work with a US car by simply bridging the inputs to Fuse 7 & 8.

A US box could be made to work on a Euro car by somehow cutting the bridge between fuses 7 & 8.

US: Both Fuse 7 and Fuse 8 gets power from the WH/VI (pink) from the High Beam Relay.

Euro: Fuse 7 gets power from the WH/VI (pink) from the High Beam Relay. Fuse 8 is NOT part of the headlight circuit, and it gets its power from the same input as Fuse 11.

Where things get plugged in is obviously different around Fuse 7 and 8.

All of this is documented here in this Excel spreadsheet:
https://kindel-my.sharepoint.com/:x:/p/ ... Q?e=xSWPOp

Image

FAQ: How does Fog Light wiring differ between US and Euro E28s?

The wiring to the US car's fog light module at the dash has two wires (YL/WT and GY) (because there's only front fog lights and thus one button):
Image

The GY wire goes directly to the input (pin 86) on the Fog Light Relay. YL/WT comes from the light switch (head lights or high-beams on).

The wiring for the US car's fog light module at the dash has four wires. GY/RD & GY for fronts and GY/VI and YL/BU for rears.
Image

As with the US car the GY wire goes directly to the input (pin 86) on the Fog Light Relay. But on Euro cars the GY/RD comes from just the head lights (so fog lights do not turn on when brights are flashed.

The GY/VI somehow comes off fuse 3 and YL/BU goes to the rear fog lights.

See this thread for retrofitting a rear fog light into a US car: viewtopic.php?t=96009

FAQ: How does Power Window wiring differ between US and Euro E28s?

(Details to come, but he essence is on Euro cars when the driver's door is open, power is provided to the power windows. This is not the case on US cars.)
More to come...
Last edited by cek on Nov 29, 2020 3:21 PM, edited 4 times in total.
Mike W.
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Re: US vs Euro differences in electrical wiring / system and fuse boxes

Post by Mike W. »

The high beam makes sense as US cars had 4 high beam headlights with the dual filament in the low beam and euros had only 2.

Kind of related, what really had me scratching my head for a while one time was helping on a 524td to 535i conversion. C101 plugged in, but the wires went to different places! I thought the fusebox itself was different, but I guess just the wiring including the connector.
BenGerman
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Re: FAQ: US vs Euro differences in electrical wiring / system and fuse boxes

Post by BenGerman »

So how would that be different when running the full euro harness from the fuse box forward?

Great work Charlie, thanks for documenting.
cek
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Re: FAQ: US vs Euro differences in electrical wiring / system and fuse boxes

Post by cek »

BenGerman wrote: Nov 29, 2020 11:18 PM So how would that be different when running the full euro harness from the fuse box forward?
I think you could swap a euro front harness right in. You'd have to figure out how to deal with how Fuse 7 & 8 are different. On the Euro front harness, the high beams are powered by two VI/WH wires that come together in a single plug that goes to output 2 of Fuse 7 on a Euro box (and Fuse 7 is 16 amp on Euro). You'd split those wires so that each has its own connector. One goes on Output 2 of Fuse 7 and the other goes on Output 2 of Fuse 8.

This would make doing the headlight wiring for a Euro conversion way too easy. Assuming you can source a front Euro harness.

Oh yea, the Euro harness doesn't have the wires for the aux fan diode, nor does it have the other 2-pin Molex connector with the black wire that I have no clue about.

See them both here:
Image
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