Hi guys just realised I posted this the other day in wrong area! so putting here in hope someone can help me! sorry for bad spelling etc.
I have also just gone to start her and battery is dead a door post so severe battery drain......please help!

XJ8 3.2 1998
Just bought this car as a returning Jaguar fan years ago, drove her 100 miles home fine, parked behind my missus who had followed me home turned the jag off and thought why has she still got her engine running ? as I got out I realized key in hand that it was the jag still running dash lights all on ticking over, i tried wiggling the ignition and taking key out again still the same......after quickly operating the starter to kill the engine i started her again and then took the key out, still the same engine kept running so did the same again got out closed the door all dash lights still on inside fan still working wipers everything apart from radio...? so i disconnected the battery, t re connected it and went to start her again where i had all dash lights but now the indicator lights outside were joining in too! and no starter engaging ??? i can here a relay in the dash click but thats it, after many many attempts of re connecting disconnecting open door close door wiggle key plastic in the dark and still no start i give up, please help me regain my love for the car.
I did note when I| collected it the boot was up, the battery was disconnected and the indicators did flash but it started and ran fine, i stopped twice on the way home 50 miles into the journey and she stopped started fine so whats happened, I also found a relay laying loose under the bonnet a light brown one so looks like this may have been a problem someone has looked for before ? ??

So to sum it up, took key out engine kept ticking over fine with dash lights on, disconnected battery now no turn over but all dash lights on with key in or out, when ignition turned to starter indicators flash and flash but no siren, any help greatly appreciated.

 

i have just replaced the battery with a 950amp range rover one that is near new and i know is good, im taking her for a run see how she goes

 

That's not a good start you've got with this car.

First off, get a new battery for it. Second, if you disconnect the battery you should hold the the ground cable to the plus to reset the electronics for like 30 seconds or let it sit for at least half an hour.

Somebody definately did something to the electric system, I would call the previous owner or the one you bought it from to get more information. Picking up a car which has the battery disconnected should have triggered your awareness of possible problems.

As for the relay laying around, just keep it in a safe place, if there is anything not working after you fixed the main problem you got an indication where it came from.

Good luck!

 

Right, posting at the same time here. LOL!

Keep us posted.

 

Hi mate
Put new battery on started went put petrol in stopped then started....got to my mechanic and took key out still running ! So he had a look base of ignition switch all ok....I went round to passenger front door opened and closed it and the engine stopped (key out of ignition ) however all dash lights on but cigar lighter off etc ( had my phone on charge ) so opened closed passenger door again lights went off ! Put key in and started again......He took relays out cleaned (front left under housing under bonnet) made sure tight fit and I stopped started stopped started.......... now getting washed won't shut off gain! !!

 

I'd check the black power cable connections that run to the two fuse boxes (front passenger side inner wing), their studs and rings etc with abrasive, assemble back up with dielectric grease.
See how that effects this odd behaviour - there's also another connection but check the false bulkeads first.

 

Well checked all suggested and all was fine, took all relays out 1 at a time and all togeather still the same, sat in yard dash clock lights on wont start, disconected battery drained charge connected still dash lights on no start AAAAAAAAAARRRRRRRRRRRRR, so myself and my mechanic looked for another fuse box inside the car..........as an pure accident he wacked the centre console and guess what.yep you got it lights out and car starts ????????? as we work our way round the car dash we found that even lifting the dash or pushing an air vent made the dash clock lights go on and off and decided weather the car was going to start or not, we removed the dash clocks and after wiggling the wires it started stopped again and again then put them back and did same again lights on clocks no start !!! we have decided that there must be a wire in the dash that's gone bad and we are going to strip it next week until then she runs perfect and nearly always turns off with the key! if not I have the odo reset switch that i pull slightly and she dies! ever heard of this before ? all this new age electrical stuff is great really great a !
I have driven her for 10 miles today faultless not a miss of a beat anywhere just this odd connection disconnection business ?

Any ideas ? we are going to strip but if anyone has an idea ....also someone has deffo been there before us loose screws etc so did they miss something important ?