Electrical panic...

[mariobucolo]

Hi, I'm sicilian living in London, I have an XJ8 3,2 1999 here in London and in Italy I have a bunch of classical cars.
I turn on the car and I see that the instruments light blink
after 100mt I receive the message "gearbox fault" and the gerabox set to "home" mode. A minute and the instruments light off, Stability crontrol allarm, airbag light on, ABS light on.
When I stop the car I see that the most left headlapm was off, I took out to buy new one...the day after i find the battery totally off (with indicator set to change battery). I suppose the electrical problems was due to the battery. Buy a new one and when I turn on the car...again all the same message about gearbox, stability etc, instruments light off (the initial check is all ok) and this time all headlamp don't work, as don't work the emergency blinker and not work the direction lights both if i try with the emergency button and bot on single activation. The windscreen work. Appear there is a big problem on the electrical circuit, probably a short circuit. The ground cable connected to the battery become hot after few minutes. I check the headlamp bulb, the one that was off at the beginning but appear ok.
Any idea how to can solve?
I just order a obd scanner hope if this will help.

I'm worried to go to a normal workshop as I risk only to pay a lot of money for few help.
I live in London Bermondsey area.
Thanks
Mario

[J44EAG]

Hello Mario.

The OBD reader will certainly useful.

If you have a hot wire then this needs immediate investigation. The fire risk is great, so I would suggest you enlist professional help with what is perhaps a major fault.

I am sorry not to be more helpful.

Mike K

[Brakebuster]

a ' HOT ' cable or wire can indicate heavy load, or high resistance ,

the negative battery cable , that is bolted to the body is a known problem when it gets corroded, as it returns a very high resistance back the the battery

this can be perceived as a poor battery , as its almost the same as the voltage isn't able to complete the circuit without going through the high resistance of the cable, causing the heat.........

i would check the condition of the negative lead for green corrosion to the copper , some exposure of the cable might be needed

usually this manifests its self as green ' dust ' in between the cores , a sure sign the cable is deteriorated beyond use

i think new ones are hard to come by , but good used ones should be fairly easy to obtain

BB

[Brakebuster]

a quick search turned up brand new jaguar stock from jaguar dealers

part number XR840827 @£41.00 plus VAT

if that is your issue mind ?

BB

[mariobucolo]

Thanks, I buy an OBD reader but after connection doesn't go trought, appear to don't be compatible with the X308.
Yes I want a professional expert but i have difficult to find one in London and in my area (SE) as i don't want to drive a lot with the car.

[mariobucolo]

The cable appear in good condition

[RichardSEL]

In southeast London I use Surrey Jaguar in Croydon -- they have new workshops now so check their address in their web page. Change the negative earth cable anyway. That means cleaning the battery terminals and the inside of the cable terminals to battery.
That also means cleaning where the cable spade gets screwed to the body so you have clean bare metal against clean bare metal

You do not have to pay £41 (+VAT?) for a cable that will only be crimped to its terminals. A repeat of what you have already.

Go to an electrical (house wiring) shop and ask for 60A tail in black. Of the same length. Or take your old negative cable with you. Then get a spade terminal of the correct size from there. If they don't have them then go to a motor factors shop for the battery terminal and the spade terminal. Connect those by first tinning with solder the new copper cable ends. If you have not got the skills then ask an electronic repair shop to do it for you.

Total cost will be about the same but you will have a superior product. If you buy a replacement negative cable from the independent factors shop (again cheaper than Jaguar prices) see if you can find someone to solder the cable ends for you. The terminals are only crimp crushed onto the wire so that's why they get dirty and give a bad connection after some time

After you fix the fault (either by new cable or new battery or even both) you will have to get the stored faults in your car's ECM (Electronic Control Module) cleared. Surrey Jaguar can do this but charge £30. Or you can put the £30 toward a correct Jaguar-compatible OBDII diagnostic. Not any old cheap code reader will do the job.


Hope that helps?
Let us know how you get on?

[mariobucolo]

Hi guys thanks for all your advice.
Now appear to work well a part the two external sidelamp (but will check sunday for fuse or why don't work, I need the car tomorrow so don't want to touch actual equilibrium)
What i do:
I measure the tension of the battery, more the 12v, I connect the cables and I burn my multimeter so I don't know the tension one connected.
I make more pressure to knob fix the ground cable to the battery and to the other group of ground cable nearby
I turn on the car and detach the ground cable to check if the alternator work properly and for 30/40 seconds, without accelerate the engine run (non normally but run) and after off.

I also connect again the ground cable and magically the car run ok and the ground cable wasn't hot.

So was the knob of the ground cable or I provocate a "shock" to the ECU resetting all things when i detach the cable while the engine run?
A mystery... remain the problem with the two side headlamp that I hope to solve sunday.
Thanks to every one, for now the situation appear good.