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Can anyone tell me where the brown wire on the inlet manifold connects too? I know it doesn’t go to the right hand air box as everything else is connected up. Only one I can’t find after refitting the engine. Thanks if you can help solve this mystery!,
You can meter it and see if it gives +12 all the time.
Is there anything in the engine compartment that doesn't work...cruise control, aux fan, and so forth? If so, maybe that is the power lead to the inoperative device.
I would guess that they made just one wiring harness for all varieties, and if an option wasn't included in that particular car then that wire was just left disconnected???
Judging by where it seems to come from (single wire from lower on motor) and the sheath on it l suspect something to do with starter/ alternator maybe.
l can eyeball my car later in the day.
[QUOTE=baxtor;1999015]Judging by where it seems to come from (single wire from lower on motor) and the sheath on it l suspect something to do with starter/ alternator maybe.
l can eyeball my car later in the day.[/Q.
Thanks that would help. My car is not running at the moment.
Sorry Bob, some idiot cut a fibre and we've been without internet for a couple of days.
I looked in my engine bay and I can not find any wire that looks like that, although I do have the engine support in the way ATM because I have the front subframe out.
Just checked my car Brinny and l have that wire on mine. It is the feed to supplementary air valve. This is attached to right hand air cleaner backplate.
wire is routed under throttle bodies then up to connect.
My car is UK spec, that's the only reason l can think of for difference. That wire on mine is actually brown with slate rings rather than normal lineal tracer.
l can't find very much documention (a little in the 81_88 engine info. bulletin )which includes the vacuum solonoid valve at rear of my R/H manifold which is associated with my supplementary air valve. All stock jaguar wiring.
A certain amount of guesswork involved which may possibly give you a clue 'or maybe not'
On my 1990 XJS V12
I've got the same single wire in a White connector exactly the same as you, except instead of it being a Brown Wire it is Yellow
'Not that I think that the Colour makes any difference' (although I could be wrong)
But on my Car, the Wire with the 'White Connector' comes off what I 'Think' is called the Supplementary Air Valve?
Where on my Car this Wire runs along the Top Closing Panel which covers the Rad and then goes into a Loom and then the Wires that come out of that Loom go into the 2 Silver Relays on the Top Closing Panel
Have a look at the Photos, as they may give you a clue
Single wire comes out of this 'Gizmo' and then goes into a loom
Single Wire goes into this loom on the Top Closing Panel
Single Wire goes into Loom and Multi Wires come out, where they 'seem' to connect into one or both of those Silver Relays
Last edited by orangeblossom; Dec 10, 2018 at 01:47 PM.
Thanks for that ob. I’ve got those wires connected up ok. I marked those up before I stripped the engine and reconnected them so I’m confident. It is a mystery this wire. I had another look earlier and the wire is brown with light blue marks intermittently if that helps anyone. Thank you for taking the photos and making the effort ob.
Brinny l suspect if your supplimentary valve is hooked up and working the brown/slate wire you have (same colour code as my valve wire) is redundant.
Jaguar tended to make changes and updates over a period of time rather than a clean cut off as they used up old wiring harnesses etc. and 1989 seems to have been a hot spot for such updates.
My own car is 1989 but l have come across many examples where wiring diagrams do not match what l actually have.
The supplimentary valve is such an example where my car matches neither earlier nor later diagrams but rather a bit of each, but it still works.
If everything related is working ok just treat the wire as redundant.
Brinny l suspect if your supplimentary valve is hooked up and working the brown/slate wire you have (same colour code as my valve wire) is redundant.
Jaguar tended to make changes and updates over a period of time rather than a clean cut off as they used up old wiring harnesses etc. and 1989 seems to have been a hot spot for such updates.
My own car is 1989 but l have come across many examples where wiring diagrams do not match what l actually have.
The supplimentary valve is such an example where my car matches neither earlier nor later diagrams but rather a bit of each, but it still works.
If everything related is working ok just treat the wire as redundant.
The car is a non runner at the moment so I can’t check if everything is working. I know what you mean though about jaguar and their wiring and you may well be right. This wire wasn’t marked up by me when I removed the engine also. Thanks for your input and it may have to wait until I can get her running and see what doesn’t work.
Brown wire location anybody.
