The bonnet has been off for ages, finally back on and all the wiring for the main headlights makes sense BUT the little 5 3/4 lights confuse me ... I've forgotten ... they have a wire for common ground on the body and another wire (not original) dangling ... and I can't recall where it goes or find any waiting connection to fit it to.... bemused ... not the indicator bundle .. no .. nothing apparent of the bigger headlights ... or do they piggy back off the larger ones? i can see the wiring for the fog lights (none) and a spare wire/blue with it but i don't think that's right. I thought they could operator on own .. or am I just making stuff up now
confused... help..

the little lights have earth but no obvious power outlet .. what am i missing?

 

There's an electrical guide in the US called S57. Very helpful for all maters electrical in XJ6. I've attached the headlight page from the original as wall as a modification I did to document my conversion to the UK lighting configuration (different headlight switch with more positions on my car. Either may help.

 

My S2 wiring is far from Factory Original, so these photos might be of no help at all.

Green arrow indicates the ground/earth point, a bullet connection to the radiator mount.
Red arrow is the power lead (Blue/white).
This is the Right side.


Here again, Green arrow is the ground/earth point, on the rad mount.
Red arrow is the power lead (Blue/white) which is also a bullet connector.
This is the Left side.
(';')

 

To clarify does it draw/share power off the main headlamps tho? or have i lost an entire connection somehow/

 

No.
Power comes from the main headlight relay.
As a picture is worth 1000 words, I'll add a couple:

Here you can see the Headlight Relay, aft the radiator mount, wires branching to each set of fuses, wires continuing on to each fixture.

You can easily trace the Blue/white wire back to the fuse boxes and back to the relay.
(';')

 

so in essence after the relay we go to the fuse box and at at the fuse box the high beam signal heads to the large light and the low beam signal to both the large and small light ? my wiring has been revised so much by so many i am being fairly linear about it to make sure i am getting it., you know before i blow stuff up.

 

On my S3 the blue white wire to the main headlamps is spliced to feed the main beam and the 5 and 3/4 additional main beam. The common earth is nearby as shown previously. Been cleaning all my contacts to get them working properly. The blue and red wire is for the dipped beam.

 

Series 2 Headlight Circuit diagram.
(';')

 

also noticed an oddity that the white-blue wire coming down the side of the car has had a branch off added to the passenger side light before it continues to the lighting relay. the left hand lights only get their feed from the relay, surely the blue-wire should go to the rely first and then any feed to the right lamp come from there..

 

That does sound odd. Does the side light come on on its own ie without the main beam, or are they on all the time?

 

as it turns out the odd blue-white wire is 'high beam warning light' so hence it is connected to a lead to the high beam and sends a signal to the cab dash when the high beam is on .. in theory .. but it didn't seem to be connected to the high beam any long and doesn't seem to want to perform.

should the lights be fused before they reach the relay or after they depart the relay for the lamps?

even with new wire the headlights are at odds, so I figure I have still not made sense of the relay entirely..

 

Yes, Hi Beam pilot light is connected to other Blue/White wires that send power to High Beams. Goes through dimmer just like they do.

Fuses are AFTER the relay. Between relay and lights.
Notice fuses are mounted on radiator mount after the relay which is mounted aft the radiator mount.
(';')

 

Any one clarify what the diode between 31b and 81b does beside limit flow one way or prevent flow? which way is it to face ? How bets to test it?

 

Um, I think that's the Blue capacitor that's mounted under the relay can (post 5 above, second photo), although I could be completely wrong as the Brits seem to have had their own ideas on such things.

If it is in fact a capacitor (as it would be in Mercan cars of this era), its job is to keep the points within the relay from arcing/fusing while turning on/off the higher current required for the high beams.

If this component fails, High beam points can weld themselves together so the dimmer switch doesn't work. The only way to kill the high beans in that situation is to open the hood and give the relay a good sharp >SMACK< with something hard to jar the points apart, and if successful, drive home on low beams only.

I could tell you how I learned this but it's a very long story.
(';')

 

sounds like it is a capacitor from some research, yes. fairly useful from what you say, stopping stuff melting is always good.
good sharp >SMACK< noted for future ref.
until i read an older post i had inverted the blue-red blue-white wires in regards the low-high beam thinking one to be the other.
lights ad new wiring & fuses seem to be back in order only bug is The Warning Light. I run it to the relay and to the fuse box at different attempts but for some reason now the light in the cab stays on for both low and high beams..... what's the trick?

 

I've never had trouble with the high beam pilot light, so I'm guessing here, reading the diagram.
It *Should* be connected Only to the Blue/White circus.
If yours is on all the time you have somehow got it crossed up into the Red/White too.
(';')

 

strange~
i had it hooked by the fuse for the high beam, then directly to the high beam at the relay NOW tried it intersected near the left wheel hub (where it original was in odd bullet junction to the original wiring) and it still remain, altho i can see that 'hi' and 'low' give different brightness intensity on the dash board light it is still on... huh..

 

I can still measure a voltage in the high beam wires when switched to low beam. it's a drop from 11 volt at high beam on to about 4 volts with them off but it's enough to feed the dash warning light...
wonder where the power is bleeding from as the cables all appear to be cleanly separated. wonder if it's in the relay itself.

 

Could it be that the hi-beam latching relay is not fully switching from hi to low? Are you getting the 4V to the relay terminal or at the hi beam bulb socket?

 

Did a few more checks and swapped in a different relay, but same issue. not checked at the actual bulb yet but near relay, at fuses, at pilot light junction back to pilot light etc, still getting 4 volts flowing back down the high beam and powering the pilot light when it should be off. maybe i need some means to stop the leak like the diode?