Update! My wiring nightmare... where do I go with it?

[jimk]

1 hour ago, All Day said:

I'm considering going with a bulkhead connector so that I can divide the engine bay and cab into two separate looms to help make it more manageable.

Keep in mind that most bulkhead connectors have one side removable and the other fixed in place.

[bmw_e30]

i have a great wiring guy here in LA let me know

[calw]

I rewired my early '68 car entirely except for the wiring from under the dashboard to the rear lights.  I also went from the original utterly trashed 3 piece dashboard to an uncracked single piece dash, which added detailed complications.

 

I don't recommend this route for those with a day job or those who want originality. Repairing the existing wiring is probably MUCH less work

 

After-

1.  Comparing the wiring harness in my car to all available schematic diagrams and finding none that were a complete match

2. Finding enough crusty cracked insulation in the engine bay

3.  Considering the idea of making a brand new copy of one of the original wiring harnesses with matching wiring and colors

 

I took the plunge and did it with all new wiring except for the simple section that goes back to the trunk for rear lights which was still in great shape. 

 

While I was at it, I decided to re-do how things were fused in a major way.  The original 6 fuse design was, shall we say, not up to today's contemporary standards.  I did not move the battery to the trunk as was in vogue for 02'ers for many years, but I did select a battery of the original size with terminals located to suit my wiring scheme (can't recall if that makes it standard or if I reversed it).

 

Reproducing a factory harness wouldn't get away from the 60's fusing design.  Buying new wire with the factory color codes would be expensive and my new design would already be different.  I had a big storage cabinet full of spools of wire and decided to use it.

 

I did look for some sort of bulkhead connector that would fit, came up with none that quite fit the bill without making a bigger hole in the firewall and I wasn't sure if one of the available connectors could be made to fit.  A significant effort went into making sure all the necessary wires went through the bottleneck that is the firewall.  

 

The 6 fuse holder under the hood was replaced by a small aluminum panel that I'll someday have engraved as a memorial to the original wiring.  Note for documentation- it would be very difficult to replace the 6 fuse holder with a 12 fuse holder, the sheet metal's different enough. 

 

I added "Mega" fuses right at the battery for every load, as is in vogue for manufacturers lately, including BMW (the actual fuses came from E92 junkyard cars).  One for the starter, one for the other loads under the hood, one for the loads in the cabin, and one for extra stuff in the trunk (ham radio transceiver).  There is also a big chunk of copper plate adjacent to the battery that serves as a serious single point ground which is carefully bonded to the car's body.

 

I put  an aftermarket ATO fuse panel under the hood, fed from one of the mega fuses, for all loads that lived under the hood- Headlights, High Beams, Driving Lights, Horns, and Electric cooling fan.

 

The Mega fuse for cabin loads feeds directly to a home made panel with fuses and terminal blocks under the instrument cluster that also includes the wisch-wascher module and turn signal flasher.   A major challenge was to fit that in what originally looked like a lot of space- it wasn't...  Several revisions were needed until one actually fit. 

 

I replaced the flasher switch with a latching 3 pole double throw push-button switch (from some sort of musical foot pedal application sold online) that fit into one of the instrument binnacle holes and rewired the turn signal circuit per one of the generic online diagrams - I was able to get everything except the single instrument cluster lamp working correctly but didn't need it because I've installed one of the Speedhut GPS speedometers instead and it has left and right signal LED's. 

 

The heater blower switch, which would normally be mounted in the right side heater control panel in a one piece dashboard, was replaced by a rotary switch that also fit in a binnacle switch hole.  The body work behind the dashboard in 1968 was not compatible with the double-slider control used for single piece dashboards, so I used an older single slider with the older face panel.

 

So the instrument cluster binnacle has Lights, Cigarette Lighter, Heater Fan, and Emergency Flasher switches.

 

This all took TIME, lots of it.  There were several iterations of what should turn on with which key switch position.  The first terminal strip I chose for under the dashboard was too big.  The second one was too cheaply made.  The third one finally fit.  I'm still not entirely happy with the fuse holders but so far so good.    Much of the work was done in a unheated Colorado garage in the winter, not recommended.  Some of it was done ..several.. times before it was right.  Wire colors are definitely not BMW standard, but everything is documented and I have a copy of that info in three fireproof safes and the national archives (well, 2 copies in different rooms and one in the trunk of the car). 

 

If anyone takes a similar plunge, I echo the other comments earlier in this thread- quality wiring, connectors, fuses and holders, shrink tubing, solder, and deluxe zip ties are your friend.

 

Original?   Not at all.  Functional? Completely.  Safe?  To the best of my ability.  Over-Fused?  perhaps, but logical if only in my mind. 

[ray_]

Masochist!

 

[irdave]

Wholey crap Cal.  I never saw the part under the dash.

 

 

[irdave]

6 hours ago, All Day said:

As I'm considering all of the work to clean this wiring up I'm considering going with a bulkhead connector so that I can divide the engine bay and cab into two separate looms to help make it more manageable.

Wondering if anyone has installed one and has an opinion on it and the difficulty in doing so?

They seem fairly inexpensive at around $50, and I figure it would save me some of the splicing I would need to do in the middle of some of the wire runs.

 

I was thinking about this when I built my new harness for the Haltech ECU, but what I found was at least a couple hundred dollars a side, so in the 4-500 range total.  All motorsport stuff, sure, but still a lot of money and a lot of potential to screw up.  Smart guy at a conference once said,"Make it useful before you make it complicated."  If it was me, I might try getting it to run right before I cut the entire wiring harness in half.  Just sayin'.

[Rob Zaeos]

Holy cow @calw!! I do not poses that much technical skill... but gonna do my best at a safe repair for now. Looks like all the colors of bmw wires aren't readily available but i plan on leaving some labels on the wires as well as a redrawn schematic for anything i change. Your set up looks really clean. I love it. Thanks for the info and photos!

 

2 hours ago, irdave said:

 

I was thinking about this when I built my new harness for the Haltech ECU, but what I found was at least a couple hundred dollars a side, so in the 4-500 range total.  All motorsport stuff, sure, but still a lot of money and a lot of potential to screw up.  Smart guy at a conference once said,"Make it useful before you make it complicated."  If it was me, I might try getting it to run right before I cut the entire wiring harness in half.  Just sayin'.

 

Totally good point. Probably better to get everything functional first and by that time I'll have a better idea of how it all goes together.

 

 

[Rob Zaeos]

Ok. I think I may be onto something here... but not sure. I pulled the headlight switch to check the connections to are all correct but none of the wiring diagrams i have match this switch. Also seems like there may be a mis-wire here.... But maybe one of you all will have some advice.

I've included photos of the back of the switch and a diagram i poorly drew so you all can see the connections.

The first one that confuses me is 58L which has 2 gray/black wires and a solid gray all to one connection

 

The second I the red wire that goes to 30 then jumper wire to 15. There is no 15 on the switch diagram.
 

So seems like this switch is from a different model... anyone know which?

 

Edited October 16, 2021 by All Day

[calw]

From my car's diagrams after puzzling out several switches with a meter- only one of which seemed fully functional. 

 

My chart might not be understandable by others- an example, 30 is connected to both 58L and 58R in either the first or second "on" position, but 56 is connected to 15 only when the switch is pulled out to the second "on" position.  looking at it now I'm a bit fuzzy on the bottom 3 lines though-  "RX" refers to the instrument cluster brightness rheostat but I don't know why I have nothing noted against 58B, sorry.

 

 

[Rob Zaeos]

9 minutes ago, calw said:

From my car's diagrams after puzzling out several switches with a meter- only one of which seemed fully functional. 

 

My chart might not be understandable by others- an example, 30 is connected to both 58L and 58R in either the first or second "on" position, but 56 is connected to 15 only when the switch is pulled out to the second "on" position.  looking at it now I'm a bit fuzzy on the bottom 3 lines though-  "RX" refers to the instrument cluster brightness rheostat but I don't know why I have nothing noted against 58B, sorry.

 

 

This is helpful! Thank you... at least I will know what this particular switch does! Gonna rub my last two brain cells together and see if i can figure out where mine are actually going.

[Rob Zaeos]

tested the switch and everything works as should... and tracing the wires it looks like it is wired to operate correctly,so i'm not gonna mess with it. Think I might have been going down a rabbit hole.

 

Spent some more time in the trunk cleaning grounds and replacing bad connections. Everything seems cleaned up there.

 

Headed to the front of the vehicle this week to trace wires and eliminate more of the extras.

Edited October 17, 2021 by All Day
mistake

[Rob Zaeos]

On 10/13/2021 at 9:38 PM, Mike Self said:

 

And...the turn signal lever has a couple of extra terminals that aren't used on US 6 fuse cars; if wired up, they allow the left or right parking and tail lights to be illuminated by selecting a left or right turn with the stalk, with the ignition off.  It's possible that a PO connected one of the turn signal wires to that terminal, and somehow inadvertently wired a tail light into the turn signal circuit.  Or there are crossed wires (or a bad ground) back at the tail lights.  The possibilities are (unfortunately) endless.  

I think Mike may be onto something here. I unplugged all of the additional wires that are not connected in the 6 fuse cars and that seems to have solved the dash and right parking lights coming on with the blinkers. I replaced the flasher relay with the upgrade PXL and I have blinkers and indicator all working correctly!

 

There is a constant faint glow from the indicator light that has me a little concerned though, possibly a bad ground somewhere? I added an additional ground behind the dash but no change. Any ideas?

[ray_]

What color is the indicator light lens? Red = likely an alternator diode issue.

[Rob Zaeos]

1 hour ago, ray_ said:

What color is the indicator light lens? Red = likely an alternator diode issue.

Guess I should have specified. It is the amber blinker indicator light. Faint glow when blinkers/hazards are not in use....

 

Edit: the mystery deepens. When I got everything plugged back in in the engine bay and checked the light it was the same... faint glow, however after starting the car, and once i rev the engine and the charge light goes off the blinker starts blinking slowly, all on its own, no switches on. Ugh. Right when I thought I was making progress... lol.

 

I feel like there was more than one issue with the blinkers... so going to continue tracing every wire according to the diagram and removing excess circuits. I'll report back with my findings ... not that this will help anyone else... I think the PO cooked up special formula just for me?

Edited October 19, 2021 by All Day

[John76]

Is the new PXL flasher relay ungrounded?    The brown ground wire on the stock 4-wire plug is not used.