Can anyone identify this wire?

[haffy]

Hi All, newbie here; first post so I hope I do this correctly. I just found a wire on my drive; figure it fell from my 1965 Etype Series 1 DHC. Short black wire folded in the middle with blue male connector and red female. Can anyone help me identify what it is so I can try to re-install it? I'd be very grateful as I'd like to solve it before I have to call the garage. I don't know if it is a clue but I had LED headlights installed and a while back the dip switch stopped working so they are currently stuck on full beam. I have been meaning to investigate and now wonder if this wire had worked loose before it dropped out.I figure that since it was on the drive it came from the engine bay rather than the enclosed wiring space behind the dash. Equally I may be talking rubbish:) Any thoughts gratefully received!

[Gfhug]

Haffy, welcome to the forum. Black wires are earth wires. The bullet end would go into a connector, sometimes a multiple connector, back into general earth circuit. The other female spade to the component. Difficult otherwise to be specific. As to it being original or new, who knows, sorry. There are many such connectors on the car, so not at all easy to say where it came from.
Maybe it came loose when the LEDs were added
Do you have the full maintenance manual with the relevant wiring diagrams? There are some in the knowledge section to help.
It could take a sparky quite a while to say where it’s from. But look for the circuit for the lights to see where the dip/main lights are connected and controlled.

BTW, please add your name and car type to your signature area by clicking on your user name top right. We can then respond appropriately for your car.

Geoff

[MSM]

I think it is fair to say that red crimp tags were not fitted by Jaguar when they originally built the car. It has been added necently(ish).

[40GT]

Along with the bullet connector which is also modern, process of elimination probably points to headlamp area, possibly a wire to a side lamp, why this would affect the beam I'm not sure.
You need to get digging really, earths first then live, although new work follows no rules regarding colour, so a black wire could mean anything.

[44DHR]

Do both your horns work ?
It could be one of the Earth wires to the two horns that are mounted on the bottom of the picture frame as sometimes these have an extra wire fitted by a previous owner to provide a good Earth rather than rely on the mounting stud to the bracket on the bottom of the picture frame.
Cheers,
Dave

[haffy]

Thanks Geoff, Mike, Sean and Dave. Apologies for the delay in responding. I really appreciate your very helpful replies. I will follow your suggestions and if successful will report back. It's nice to feel part of the Club :)

[haffy]

Quick follow up in case it 'leads' anywhere (hahaha). I updated my sig - thanks for mentioning it. The horns work so I think they are not the source but thanks for the suggestion. I now think it can't be the LED headlights as I can't see how the wire would get outside the car. I looked at the wiring diagram but no clues from that. Had a good look under the hood and I see that there is a Guardian GR7 12v 40A relay that has five terminals. After doing a bit of googling I think that two are for power +ve and -ve. One has a green wire connected to the NC terminal on my Kenlowe fan thermostat; the other GR7 relay terminal is connected to the fan itself. The fifth relay terminal is free. The NO terminal on the Kenlow fan thermostat is occupied by another green wire that comes up from the wiring loom clamped to the front strut near the radiator. Where that green wire feeds from the main loom there is also a red black wire ending in an empty black connector. (Two similar empty black connectors are attached to wires coming from my coolant header tank Otter switch). I tried the blue male of my mystery wire in the black connectors but it does not fit - seems just too large. Is it sensible to think that my mystery wire connected to the fifth terminal on the GR7 12V 40A relay and went into one of the black connectors? Just asking on the off chance. Any thoughts welcome. Photos attached of the foregoing in case they aid understanding. Thanks for reading in any event! After this it's off to the garage!