Interesting! Yes, in electronics, the sleeving that is applied to single bare wires is called spaghetti–or at least it was in my youth. I never knew why.
I thought Kabelbaum was what you’re trying to translate, because a car wiring harness has many branches.
Where are you located, Jochen? Your English is so fluent that I thought you might be in the US. And having a UK spec car doesn’t help. 
Considering that the car was prewired for fog lamps, Jochen, sometimes dealer installed as customer option with no problems - your option is a bit elaborate…
However, it will certainly work OK. To ensure co-operation between fog and low beam in ‘fog’ setting; in addition to the relay-to-fog wire - connect a wire from the relay to the blue/red (low beam) connection at the main light relay.
This is basically the ‘European’ solution to bypass the lack of blue wire power to the main relay in ‘fog’. Except that the main relay connection is taken from the light switch…
Frank
xj6 85 Sov Europe (UK/NZ)
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As a matter of fact I was impressed by your knowledge of “Kabelbaum” - much less common than kindergarten or leitmotiv!
I’m located in Southern Germany, right by the Swiss and Austrian boarder and about one hour’s drive from the Alpine range. My UK spec’d car was imported to Germany by the PO, but I’m a German who had the chance to spend great times in NZ and in the US - in 1993/94 I was living in Iowa City. Heartland US was a great experience! Thanks for the flowers anyhow! - I know I’m not sufficiently “in” your language to express things easily and directly; that’s why I’m probably always a bit heavy on the front wheels languagewise …
BTW, that’s the kind of sleeve I was trying to describe
Best wishes
Jochen
75 XJ6L 4.2 auto (UK spec)
Thanks Frank,
as soon as I’ve made up a wiring diagram I’ll probably get back to to to make sure I’m not putting the car on fire!
Best wishes
Jochen
75 XJ6L 4.2 auto (UK spec)
Near the Bodensee? I think you’re not too far from Andrew Waugh. What’s the “spaghetti” you show in the photo made out of? Looks sort of like heat shrink tubing. It looks stiff. We have a corrugated polypropylene tubing that’s similar, except it has a slit along the side so that wires can enter and exit along the length. Tubing like you show is also used here for water…as in underground sprinkler systems.
Yes, you’re right - I’m located probably right between David and Andrew. Actually, today I went to Zurich Airport with the Jag and only just returned.
The tube is not heat shrink tubing. It is a PVC in car manufacture quality. It is meant for electric single wires that can be pushed through to be protected from mechanical influences and water. I bought the quality that is just big enough to accomodate two wires that can be traced through the engine bay and out through the radiator grill to the fog lights. I’ll post pictures as soon as I’m in it.
Best regards
Jochen
75 XJ6L 4.2 auto (UK spec)
Good evening all,
it has been quite some time that I went into that fog light project … some other things came in the way, but now I’ve returned to the issue …
I decided to run the fog lights through a relay, mostly because the wiring scheme suggests that the low beam head lights are turned off, once the fog lights are operated, and this proved true when I tested the fog light position: power was on the red/yellow wire while the low beam lights went out.
So I used the pre-installed red/yellow wire (for the fog lights) as a triggering wire which I put on pin 86 of the relay and grounded pin 85.
For the operating circuit I stole power from the brown wire at pin 81a at the headlight relay (# 231 in the wiring pattern; it is always powered and not controlled by the headlight switch (# 6 in the wiring pattern) and connected it to pin 30 at the relay. Pin 87 at the relay supplies the fog lamps.
To keep the low beam head lights operating with the fog lights on I connected pin 87 at the fog light relay to pin 56b at the high beam relay.
… at least that was my plan. BTW, this kind of operation is pretty much what US buyers got if they purchased Bosch fog lamps for Jaguar XJ-S HE and XJ SIII cars - thanks Mark for the instructions; I’ll post a write-up as soon as I’ve got a functioning system.
What happens though is that the fog lamps come on directly when I put the light switch to “head”. In contrast, they shut off when I put the light switch to “fog”. The high beams operate and - even better - then the fog lamps shut off automatically.
So, my first idea would be I got the connection to the high beam relay supplying the fog light operating circuit right: obviously, the fog lights come on - so they’ve got to get power - and they go out when high beam is on and pin 81a at the high beam switch is no longer powered.
However, I must have messed up the reverse connection: instead of powering the trigger at the high beam relay while the fog lights are on and the regular power supply is dead, I have connected the operating circuit of the headlights (pin 56b at the high beam relay) with the operating circuit of the fog light relay … aargh. Basically, I have spliced in an extra set of low beams 
So, I need to reshuffle the wires: in fact I want the trigger at the fog light relay (pin 86) to also supply the low beam head light (pin 56 at the high beam relay) at times when it is not powered due to the light switch in position “Fog”. Please, tell me I’m right … well, probably Frank has already told me to do it like that one year ago, but I didn’t understand …
Thanks again
Jochen
75 XJ6L 4.2 auto (UK spec)
**
The ‘low’ beams are meant to ‘on’ together with the fogs, Jochen - you don’t show the fog relay the diagram…
If you indeed have power to the fog lamps in ‘fog’ from the light switch, red/yellow. Or indeed this position triggers your fog relay - connecting the jumpwiring red/yellow to light relay 56b should solve the problem.
The red/yellow should now run the ‘low’ beam from the light switch - while also triggering your fog relay for fog power. And the light relay should operate in ‘flash’ - but will not hold ‘high’ beam…
I’m not sure how much you have bastardised the wiring - so further info may be required…
Using a relay for the fogs is perfectly OK, but whenever the fogs are triggered by the ‘low’ beam; the fogs come on with the ‘lows’. You need a separate switching for the fogs - which originally was provided by the light switch’s ‘fog’ position.
Frank
xj6 85 Sov Europe (UK/NZ)
**
Thanks Frank,
I haven’t touched the wires and from what I’ve found they seem to be entirely original.
Getting back to the car today I found that I must have torn away the ground leg of the triggering circuit of the fog lamp relay. That explained why there were no more lights with the head light switch on “Fog”.
For the moment I removed the connector between pin 56b at the the high beam relay and pin 87 of the fog light relay.
Fully in line with my expectations and the operation described in the OM (p. 12) dipped beam headlights operate in “Head”, but are turned off once the light switch is moved to “Fog”. Then the fog lamps go on, and only the side lights remain on. This is good as it confirms my expectations and brings the operation in line with our traffic regulations which permit head lights to go out as long as side lights remain on with the fog lights.
Nevertheless, I would still like to achieve that the dipped beam outer headlights remain on with the fog lamps. Unfortunately, it seems I cannot achieve this by powering the dipped beam outer headlights from the red/yellow fog light source, as inevitably the same connection would keep the fog lamps powered while the dipped beam outer headlights are on, i.e. on position “Head”.
The only way out, it seems, for my idea of the setup would be a diode.
The setup used for US SIII cars I got from Mark makes use of the wiring harness underneath the head lamp fuse box at the left side of the engine compartment. From this point the instructions tell to steal the power for the fog lamp relay and also to connect the red/yellow wire to. Unfortunately, while SII cars do have a head lamp fuse box there seem to be no wires underneath. Either wiring changed from SII to SIII or US cars had a different setup.
However, I could adopt their way of thinking which basically runs the dipped beam outer headlights over pin 87 of the relay and leaves the red/yellow switch for the fog lights unaltered and connects them to pin 85 of the fog lamp relay.
Maybe I find some time over the holidays for a new attempt - thanks again for your help
Jochen
75 XJ6L 4.2 auto (UK spec)
**
This is sheer nonsence, Jochen - must have had a senior moment…or Christmas spirits…
The earlier light switch has 5 terminals, as shown in your diagram - the latter version has 6. Two of the terminals are separately powered in ‘fog’; one connects to the fog lamps - the other connects to the light relay 56b.
When out of ‘fog’ these two are unpowered and separated - preventing the power from 56b in dip position from powering the fogs when not in ‘fog’.
It is essential that dip position cannot power the fogs when not in fog - hence the relay 56b and the fog lamps must be separated. Without the proper 6-position light switch; a separate switch seems required to control the fogs…
Frank
xj 85 Sov Europe (UK/NZ)
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These regulations seem at variance with the common and enforced rules in other countries, Jochen. In most countries it is prohibited to drive with only fog lamps lit - dipped beam must also be on…
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As explained in the previous post; the secret is in the light switch difference. With the latter, S3 after 82, switch it is possible to keep the dip ‘on’ and no fogs, or combine fogs and dip - using only the light switch.
There is no problem to tap power to the fogs/fog relay from any low beam wires (or light relay 56b/blue/red). But unless this connection is interrupted when fogs are not wanted - is a separate switch disconnecting dip from fogs. In short fog power must be separate from ‘low’ beam power…
Indeed, the wiring diagram for S2 conforms to your results; No dip in ‘fog’ - there is no power to dip (blue wire). possibly legal at the time in your market, but now illegal (as far as I know) in Europe (and certainly in NZ). Same apply to high beams; not allowed with fogs (which would be pointless anyway). Other outside lamps lit - and ‘flash’ function intact.
The easiest solutions is to change the light switch to the latter version. I trust it is not illegal to have ‘low’ beam with fogs?
Frank
xj6 85 Sov Europe (UK/NZ)
**
Does not make sense, but is the way our Mercedes is wired. Low+fogs.
I think fog only would make much more sense. Maybe it is the way it is so oncoming traffic can see the low beams - but…
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It’s arguably necessary to augment the light from the fogs with the ‘low’ beam when driving at night, David…?
It’s of course a matter of safe driving speed; the low mounted fogs, properly adjusted, doesn’t reach very far. And certainly; using ‘low’ beam is keeping with ’ see, and be seen’?
Main point in fog is that using ‘high’ beam is completely counterproductive due to backglare - hence disabled in ‘fog’ setting…
Adding, of course, that in most countries it is illegal to use fogs except in fog and other conditions of bad visibility. Incidentally; ‘European’ Jaguar were fitted with, and used ‘rear’ fog guards - which cause no end of misery to following drivers when left on in clear weather…
Frank
xj6 85 Sov Europe (UK/NZ)
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On further musing, Jochen…
Since you already have the relay; using relay brown connected through the relay to light relay 56b (blue/red).
Then connecting the red/yellow from the light switch to operate ‘your’ relay - and(!) to power the fogs directly.
With the light switch to ‘fog’ the relay is energised and brown power delivered to low beam. The fogs themselves being lit by the blue/red.
With the light switch to ‘head’, there is no power to on the red/yellow. ‘Your’ relay ‘off’, with no feedback from ‘low’ beam…
This defeats your original intent with the relay, but it will work. And you can always fit one more relay to provide brown power to the fog lamps for your original purpose…
Actually, there are likely other ways of skinning this cat - and you may already have solved it satisfactorily…
Frank
xj6 85 Sov Europe (UK/NZ)
**
Thanks Frank,
yes, maybe you’re right: in one of my last posts I wrote that my idea was pretty much what US customers got, as the installation instructions supplied by Mark were also using a relay …
At first sight, yes, “pretty much” maybe - but following my “forced process of enhanced understanding” I looked at that diagram again and found out that they weren’t even using the relay to power the fogs, but in fact to power the outer head lights. As soon as I find some extra time I’ll try to make this arrangement work for me …
And, yes, David, for “London fog” conditions fog lights only may be superior, but for most situations of snowfall, heavy rain and fog the combination of low beam and fog is way better. In fact, in most cars you can turn off the light with the fogs on and - if you try - you’ll feel quite left alone in the dark. The fog lights have a very limited range and basically put light on the 10 yards ahead and sideways just to tell you where the road may be under a closed blanket of snow …
I never experienced any car delivered to Germany with the fogs and low beams not connected. There is an express exception though for fogs with two sidelights in our traffic regulations - maybe a result of the British EEC accession negotiations in 1972, but this is just phantasy.
I sure will report back
Jochen
75 XJ6L 4.2 auto (UK spec)
**
It will, Jochen…
Bear in mind that the fogs are designed to be run directly from the light switch - a relay to reduce light switch loads is not necessary. However, as said; if you insist; you can add a second relay for that purpose. Both powered by brown and triggered by red/yellow…
Frank
xj6 85 Sov Europe (UK/NZ)
**
did I send you the wiring diagram for the factory fog lights? do you need or want it. Sorry too lazy to read the entire thread. 
Yes, Mark, you did - and thanks again! Unfortunately, for me, the ex-factory wiring for SIII cars seems to be different from SII cars. But I’ll check and see if I can mimick the SIII installation as per your wiring scheme.
Best wishes
Jochen
75 XJ6L 4.2 auto (UK spec)
I will also check to see if I have a manual supplement for the fog lights. They were standard equipment on the Sovereign series III.
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The main difference is the light switch, Jochen - and the S3 was wired for rear fog guard lights. Not installed in S3 ‘US’ - but the wiring should be there…
Frank
xj6 85 Sov Europe (UK/NZ)
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