Fuse Box Swap: Late E24 -> E28

[Murfinator]

There has been some discussion in the past regarding fuse box swaps to get away from the old torpeado-style fuses. I've experience problems in the past with fuses becoming loose and components such as fuel pumps not working and the car refusing to start at inconvenient times. I'd like to create a thread that outlines the swap process so others can perform similar swaps to upgrade their electrical system to be more reliable.

Because I'm now neck deep in the swap I'm looking for advice from anyone with knowledge regarding the electrical system and especially the fuse boxes for the E28 and late (1989) E24 635's. My intent with the swap is to get away from the old torpeado-style fuses and upgrade to the new blade fuses. Also, the circuit board in the E24 fuse box does aways with a lot of wiring. Therein lies part of the problem: which wiring is redundant? The next problem I have is in identifying which wires from the E28 chassis belong in each fuse location in the E24 fuse box.

Below are diagrams from Mike in Louisville from whom I purchased the E24 fuse box in February. He supplied a few diagrams of the E24 fuse box seen below. The relays were marked and transfer of the E28 wiring to the relays appears fairly straightforward.



Here is the text accompanying the above diagram:

1. High Beam, Right
2. High Beam, Left
3. SUPPLEMENTARY FAN
4. FUSE 5
5. FUSE 13
6. FUSE 6
7. High Beam, From Fuses 1 and 2
8. FUSE 4
9. Fog Lights, From Fuses 29 and 30
10. Low Beam, Left
11. Fog Light, Right
12. Low Beam, Right
13. Fog Light, Left

Questions:
- Do the numbers on the left (1 - 13) correspond to the fuse position on the E24 fuse box?

- Does the description on the right relate to the E28 wiring to be attached to the fuse position on the left?

- Is it the other way around?
- E28 fuse position on the left and the description on the right is the fuse position for where the wiring should be attached in the E24 fuse box?

- Are the wiring colors the same between E24 and E28? Is 'VI/BK' in an E24 the same circuit as 'VI/BK' in an E28?

Here's a diagram of the E24 635 fuse box but aside from the coloring of the wires there is no description of which circuits are attached to each fuse position. Could definitely use some help here also:


E28 fuse box cover: 17 fuse positions numbered vertically from left (1 - 6), center (7 - 14) and right (15 - 17)


E28 fuse box underside (several of the connectors had melted)


E24 fuse box top. Relay positions marked. E28 wire terminations marked. Where to place the terminations in the fuse box fuse positions in question.




E24 fuse box bottom.

[TheLazyDog]

Far out.

[demetk]

Looks like a nice blank slate of 30 fuses to work with.

Two unloader relays on the e24 box vs one unloader relay on the e28 box. The e24 box has more fuses on the unloader circuit but the functionality is the same.

Low beam, high beam & fog light circuit on the e24 box is different by again the functionality is the same.

The e24 circuit board supplies the input power to each fuse and the output power has the actual wire socket.

My feeble attempt at the mapping. This needs to be vetted, of course.

[Murfinator]

demetk: This is exactly what I'm looking for! Thanks a ton.

[Mucci]

Was this ever completed? I'd love to get rid of this torpedo crap box.

[ldsbeaker]

I was just looking at the e24 box i had yesterday...

[Murfinator]

Was this ever completed? I'd love to get rid of this torpedo crap box.

Yes, partially. I have the box in place and wired but I'm still weighing options regarding starting battery placement (I'm running a second battery in the truck dedicated to the audio system, thus the isolator mounted near the fuse box).

I'll post at a later date with details regarding part numbers of the fuse box terminals which must be used in lieu of the OE E28 terminals which are too wide to fit the E24 fuse box. Also, most of the wires had to be extended in order to reach the necessary locations. Also notice the fuse box base is larger and the external relay and wire harness locations are different from those of an E28. This requires some time with a Dremel and a soldering iron. It's a very tedious job but given personal experience, a much needed one.

[delorean175]

Hey Murfinator did you ever get things worked out?

[delorean175]

I have an e24 fuse box setup now but don't see how the wire bundle fits into the side of the fuse box. The hood air shock mount is right in the way.

[tig]

Mufinator: Any progress on this?

I really want to make this work.

[delorean175]

I'm not sure if hes active anymore. I sent him a message last April but he didn't reply.