Jaguar Repair: Big ol problem, xjs v12, dead fuel

Question
QUESTION: Hi Howard,
many thanks for your help before with my 1985 XJS v12 HE. It turned out as it was sitting for so long that the cylinders were washing out. Now all fine albeit in need of a tune.

I have one major problem which clearly I must have contributed too. I will explain what I did first and then the outcome. The drivers window is not working so i removed the centre tunnel area to check the switch. Swapped the switch with the passenger side and it worked so ruled that out. I checked for voltage on the switch feed and it was showing 12v so i concluded that the problem was in the mechanism or a relay. At the same time i found the issue of interior lights not working which was a cheap door switch not working, i sprayed some switch cleaner and tested it but it was beyond repair as spring was not strong enough to push it out all the way.
I then checked the fuses on each side of the car just to check they were all working and removed fuse no 7 drivers side ( RHD car ) the fuse flipped up and fell behind the cover, so I removed this and recovered it.
I went to start the car to head home and every guage on the dash is dead. Fuel, temp, oil, speedo, rev and main computer as well as indicators. So basically zip. The car started fine and got me home ok. I cant see what has happened as i was careful not to disturb anything but clearly something has shorted or happened for all of them to die instantly.
As usual i dont know where to check first as all the fuses seem fine on both sides. I re traced all the steps I made and couldnt see any connection missing or misplaced.
Any help you have would be most sppreciated as im really stuck without these.
Thanks

mark

ANSWER: Hi Mark,
#4 fuse powers all the instruments. What do you mean "all the fuses seem fine"? Did you test both sides of each fuse with a test light or volt meter? Or did you just look at them?

You need to test one circuit only of what don't work. I have a diagram of each circuit individually but it is the US version so I don't know if the UK is the same. If you don't have a diagram I can put one on my web site for you to copy.

If all your instruments failed at once it is obvious that that one fuse was disturbed or is not making good contact and a test light or volt meter test is the only way to know.

If you need a diagram of the window circuit let me know and I will put one on my web site for you.

Howard

---------- FOLLOW-UP ----------

QUESTION: Howard all fine, i didnt realise how poor the old glass uk style fuses were. Bascially i merely touched the fuses and the fault was in the terminal holder on fuse #4 :). Oddly enough I must have brushed passed the brake switch too because the fault there was bad contact on the top where it meets the terminals.
Sadly the air blower now doesnt work so I am hazzarding a guess its a similar fuse problem here also when i press the brake pedal a bulb light shows on the dash. Quite handy as I know the brake lights are working but not sure why its there?
Currently there is no compressor on the car hence no belt so how much difference this makes to running I do not know since I think the same belt works something to do with emmissions although not sure about this.

Although running far better than it did, I am still sure the baseline fuel is too rich still so im going to see an old Jaguar Specialist to give the old girl a proper tune up and oil change.

Once again thank you for your valued help I owe you a beer next time I visit USA :)

Answer
Your welcome Mark,
Doc says as far as beer goes I can only have Bush NA now. ha! (non alcoholic).
If you run into a wiring issue I have individual diagrams for each section of the car so if you have that need, let me know and I will put it up on my web site so you can copy it.
Howard