1998 XJ8 V8 4.0 had a drain caused by the telephone system stationed under the armrest, it drained the 2008 battery so low it wasnt coming back PS IN FLORIDA. I placed a NAPA OEM battery in three hours ago and car still said dead battery. All inside components work fine, all positive posts are getting current, alt getting current all fuses good except a 5 amp in the rear healboad from the telephone short other than that I am stumped I cannot even think of what this could be, please let me know if you have heard of this.

 

Crystal, from the sounds of things, you have 1 of 3 problems. Now, the trick is, can you determine what is causing what you are seeing. First off, open the hood of your car and locate the alternator. If you look at the alternator, you should see a plug that has a gray/white wire and a white/gray wire (the gray/white wire will be a gray wire with a thin white line on it). You will need to start the engine and then connect a multimeter between the gray/white wire (red lead attached here) and chassis ground. You should get something over 12 VDC. If you are getting 0 VDC, then you have a bad alternator. If you are getting 12 VDC, then you will need to access the back of the instrument cluster. Again, with the motor running measure from Pin 22 (will have a gray/white wire there) to chassis ground. If you have atleast 12 VDC there, then you have a bad instrument cluster. If you don't have 12 VDC there, then you have a bad wire between the instrument cluster and the alternator.

 

What is the battery voltage? What happens when you try the starter? What happens when you turn the lights on?

You mean voltage. Big difference.

New batteries are usually 'charged' only by the fact that there is new acid on new plates. While that is usually good enough to get a car started it is no guarantee.

Anyway you can 'jump' the car to start it and take it to NAPA to test the charge condition?

 

lights inside and out work fine all all components have full 12.57 on the meter everything looks great but when i turn the key nothing like a dead battery and the battery light is on the dash

 

when i say all positive posts that means that I have located all positive charge points on the car, usally located around all fuse boxes and TCM box and they all get current

 

Crystal:
Testpoint was trying to help you use the correct description of the presence of electricity being at the "charge points". What you are measuring is the electrical potential, which is "voltage". You said "current" which is the FLOW of electricity.

He was only trying to be helpful, since as you get further into troubleshooting an electrical problem, the difference between these concepts can get very important. For instance, you read the 12.5 volts while no current is flowing. But if you turn on the headlights, (thus making some current flow) do you still read the same voltage? Is the voltage the same when you turn the key to the crank position?

With just a few more tests with your meter, you will be able to figure out whether your battery has anything to do with this.

 

I apologize I cannot start the engine and in your post it states while running please advise this is the trouble after drain due to short new OEM battery will not allow me to start the acr

 

Thank you for correcting the term I am new at this ans appreciate the help for sure, My manual states that a cold crank will not post a 12.5 it can drop to as low as 7.1 during a start so I never checked that I will try it and see. Just incase I was advised to due a fast start jump even though the battery is new I did it and still nothing, its almost like the battery is flowing to everything but car does not recognize it?
I have always spoken to Rich 15yr Jaguar Mechanic and he has never steered me wrong he suggested the following and I am getting ready to go try this.
Honestly you are not the first one to have the coffee spill issue. That fuse #5 (5 amp) in the passenger side heelboard fuse box is for the phone system only so if blown or removed it should not effect the starting. I would recommend a hard reset and yes disconnect both battery cables and touch them together for a few seconds as this discharges the capacitors in all modules and will not damage anything. Then reconnect the positive cable first then the negative last. I am wondering if we have a security system problem causing this but only a Jag factory tool can read any security faults. Next go under the hood and in the passenger rear of the engine compartment and locate the battery connection on the plastic housing. Pull back the rubber boot and see if the 13mm nut is tight and that cable lug is burnt as that may also be your problem. Lets go to the starter relay located in the Engine Control Module housing in the passenger rear of the engine compartment where that battery cable connection was. Remove the cover and the torx screws on the ECM housing enclosure. The starter relay should be the second one in from the engine side. Remove it and with a voltmeter make sure you have battery voltage on pin 1 (white/pink wire) and pin 3 (brown/white) on the relay socket connector. If you have power on both then use a jumper wire and jump pins 3 brown/white and pin 5 white/red wire of the relay connector to see if the starter engages.

 

touched the pins together strter worked

 

Remember that procedure. It will help many quirks on these cars. Just like re-booting the computer you are posting from!
Glad you got it.

 

spill caused short in console phone and drained battery, replaced battery, checked alternator, starter on pins cranked fine, relays fuses all positive joints getting 12.57 from battery all inside lights and controls work fine 100% power yet car will not start, I turn key hear nothing but open, no crank acts like dead battery

 

PS Red warning light on J Gate does not light up when I attempt to start it