So the casing for the headlamp switch has split, making my lights intermittent at best. Today while digging in there to see what I could see, I stumbled on this:



I'm assuming the burnt wire and missing relay are related. I'm also going to wager that they're related to my nonfunctional fog lamps.

Question is, where do I go from here? Replace the burnt section of wire and install a relay, or is there something else I should be on the lookout for?

 

Cut back and replace the damaged area, yes....but you must find the root source of the problem! The smoke escaped from the wires for a reason !


Cheers
DD

 

Check the fuse for that circuit is the proper rating

 

That could have turned really nasty , in my experience wires that are over loaded burn/melt where they are constricted ie through grommets or wrapped tightly in a bundle of wires which in turn melt others , it will be a pain of a job but I would trace that wire and make sure it has not melted else where . I do wonder if that relay was pulled because of the burning or whether or not it was for an option , like maybe a smoke detector.
A wiring diagram would help you to trace that wire .

 

It has just occurred to me that it may be easier to just run a new wire and hope nothing else has burned , obviously as already pointed out you need to find the source of the problem , something is drawing major amps . You would think a fuse would blow and that makes me think this wire may have been in this condition for a while maybe a long while .

 

Thanks for the tips, fellas. That wire is split and burnt the whole way along. Didn't damage any of the other wires, but it did split a coil of electrical tape that was holding the bundle of wires together. Replacing that doesn't seem too hard, from there I reckon I just need to make sure the fuse in that circuit is correct, and figure out what kind of relay I need.

Any ideas for that last one? I'm in my cups right now or I'd be out there fighting gremlins. I've got a spare 30amp 5-pin relay on my desk, but I don't want to turn my beautiful Savannah into an insurance claim.

Heck, if all else fails, anyone got a source on a bottle of that magic smoke?

 

I am trying to do some quick research on the lighting system but at this stage I would recommend that you do not plug a relay into the connector , I am not convinced that it is a relay connector .My wiring diagram is for a 78 model , yours could be different , it does not show any relay for fog lamps just a 25 amp fuse . Hopefully a member can confirm what that connector is .A couple of questions , did you smell burning before pulling out the switch mechanism ? , secondly apart from your fog lamps is every thing else working ? Is there any non Jaguar accessories fitted ? . What do you mean by " intermittent" headlamps ? ok more than a couple . Proceed with caution .

 

There is a relay for the fog lights.

 

That's a help , do you know the location of the FL relay ,I would be surprised if it is not with the headlamp relays . Just trying to rule out the mystery connector from the equation as being for the FL. It may well be that the " split " headlamp switch may be responsible for the burnt wire as well as the "intermittent" ( I assume flashing off and on ) headlights.
It would appear that Jaguars were all wired the same for any given year and depending on there world wide destination would have different warning buzzers and lights and chimes etc etc to suit the requirements for that destination. Could the mystery connector be for one of these . I am careful with electrics on electronically controlled vehicles it does not take much to " upset " them .
It may be worth testing said connector with a meter to give you more info .

 

There's no burning smell, the damage has already been done. My guess is that there was a problem and one of the previous owners simply had the relay pulled after the event that fried the wire. Everything else works, and there aren't any non-Jaguar accessories associated with the lights, and by "intermittent" I mean the headlamps would flicker occasionally - usually if I bump the headlamp dial or hit a particularly vicious pothole. I attributed that to the headlamp dial casing splitting, most likely due to age and brittle plastic. That I've managed to correct, however.

Thanks for the diagram! It looks like I only have that one wire to worry about, seeing as how the only burnt wire in the bunch is red with a yellow stripe. Just need to figure out the specifics of that relay now.

Work has been kicking my *** so I'm just going to get back to the whiskey for tonight, maybe pick up some goodies (which may or may not include a fire extinguisher) at the hardware store Friday and start my tinkering this weekend.

 

Here is the location diagram

 

OK , I am surprised , but at least it is getting somewhere , I have been asking myself why the wire got so hot , could it be possible that the FL have the wrong globes /bulbs and are drawing more power than recommended ?

 

TO fault find any power fault you need an incandescent bulb, these are still available for Oven lights. I use a couple in parallel.

You put them in series with the power and they will dissipate any high current draw without damaging surrounding circuitry, including wiring.

That looks like 15amp rated wire to me so 2 100 watt globes in parallel will dissipate 17amps at 12V.

Replace the wire and leave it unconnected at the switch, place the globes in series with the new wire.