Hey guys,
I want to find out wha this is? Maybe its an alarm? If it is I would like to go about getting to work again.

Look forward to your correspondence

 

Clearly an aftermarket switch. What it controls could be anyone's guess?

Seems too "out in the open" for it to be security related.

 

I take it that it doesn't "currently" do Anything. Trunk release? Ignition cut out? Trace the wires and see where they go. Usually wiring for add on stuff isn't buried too deeply. Poke around and see where the bright red solo wire comes out. Good luck.

 

Jerry!
Wow thats quite and inventory you have. I will trace the red wire and see where it leads and let you know.

Thanks again

 

Hi Duke

Just a guess but it could be an Auxiliary Fan Switch?

 

Hey,
Thanks for your guidance I will have a look tomorrow. It does light up red if you switch the switch. I'll post on here if I find something, watch this space

Thanks

 

Hey!
I opened the under dash section today. My horn is bypassed to a push switch to the left of the small switch we are investigating. Looks like they are connected. Please see images.

Im really confused as to what this small switch is.

Look forward to your comments........

 

There is also this loose connection coming from the ignition, circled in dark blue. Any ideas?

 

I too have that loose connection. The 2 wires together. If anyone knows what there for then I'd be pleased to know too.

 

Brinny! You have 3 XJS's!!!!!!!!!!!!! How do you pick which one to drive??????

 

Hi Duke

That Switch could be to eliminate the very same problem I had on my 1989 XJS

First off all the Immobiliser fitted to my Car was a real nightmare! especially when calling in to a Garage to get fuel, as you only had a limited time to put your keys in the ignition and move the dongle on the Key Ring to Switch off the Immobiliser before the Horn went off

Same when getting her out of the Garage at night, where the Horn could go off and then annoy all my Neighbours

Same when getting her MOT Test as when they turned the Ignition off then after about 60 Seconds the Horn would go off and the MOT Tester wouldn't know how to turn the darn thing off

Where I had the very same mystery switch as you do, which was to turn the Horn off, so that it wouldn't get triggered if you were not quick enough to put the dongle on your key ring near enough to the Sensor to turn off the Horn, so that it didn't annoy the heck out of everyone (including me!)

This had been fitted by the previous owner, where like yourself it did take a while to sleuth out, so maybe that switch does exactly the same on your Car

 

I don't have an alarm or Immobiliser. Or maybe I do and I just don't know it? How can I find out? Sorry I feel clueless :/

 

Hi Duke

If you've got a 'Dongle' thingy on your Key Ring, then the chances are that you do have an immobiliser

But then again at the very least it would be quite unusual not to have a Factory Fitted Car Alarm and if you do they can also be a PIA, as they can go off without warning and even if it doesn't go off could run your Battery down, as the Sensor is always listening out for a Signal

As for me the Immobiliser that was on my Car, was such a total PIA that I took it out, which was so simple to do that it beggars belief!

Taking a look at your Photos and the bodged up wiring with the Insulation Tape (same on my Car!) it looks as though you may still have an immobiliser in there and the PO disconnected it

Hard to say for sure but that's what it looks like to me

And so it does seem highly likely that the 'Mystery Button' is something to do with disarming the Immobiliser and or the Horn

 

REMOVED my LoJack… rusted open and the battery test BAD...
might be unrelated, but now
no voltage to the pink black wire on fuel pump relay.

thinking of re-eclosuring it and new battery.....

 

I am down to the 5.3 convertible now and a 2001 xkr. Can seem to update my profile

 

My mystery dash wires in virtually the same place as yours

 

My XJ6 has the same plug with p/gr & p/w wires. I have about 6 different wiring diagrams for the car for different markets. In some markets the wires were for a buzzer when the headlights were left on when ignition was switched off.
Apparently the same harnesses are used but wiring not needed is left unplugged. It took me for ever to work that out. Maybe it is the the same on XJS’s.

 

Think you might be right. I don't have a dongle with any of the keys. But as you can see the horn is re-routed and this is because it used to go off when turning left and right!
Have you had an alarm on your car? I think I need one but not sure which would suit the car best.

Any thoughts appreciated

 

This makes perfect sense! And I would like that feature on my car. I wonder how I could get it working. Found this in the USA,

https://www.ebay.co.uk/itm/OEM-85-91...MAAOSwpuFaExqV

Any thoughts??

 

That sounds about right. I know xk8/ xkr looms have wiring for every possible extra and if not required are just left. If everything is working when I finish my resto I obviously dont need them!