Changed Battery still reads battery - Cars & Trucks

open glove box, read the users guide
if lost it is free from JAG dealer.
it cover all that.
and yes all cars on earth , the battery can be changed
with no damage done. for sure,100%
but you need to read the manual first.
and remove NEG LUG first
first off , last on.
cars with rear batteries have special rules for JUMPS
do not fail to read the manual or damage will happen.
cars with rear battery have a way to open trunk with battery dead, (all do) some are behind rear seat access others a cable latch lever to trunk lock.
SOME HAVE HOOD UP , JUMPER POLES

best is ask here, the manuals are hens teeth now. users. or buy one on line from scalpers.

https://www.jaguarforum.com/search/47893/?q=XJS+BATTERY+DEAD+HELP&o=relevance

Security light staying on? reset it. Ten minutes on, thirty seconds off. Try to start. Relearn is three times this. Start after the third time.

Have you checked the fuses in the fuse box under the hood, check the large 120A alternator fuse and the other 40A and 30A fuses with the clear plastic cover on them.

Disconnecting the leads from the solenoid,avtivating the switch, and reading 12V is normal because you are not reading anything but the signal applied to the solenoid.You need to attach the leads and THEN activate the switch and read the voltage across the terminals.12V would mean the solenoid is good because a voltage reading is a DIFFERENCE of electrical potential.If you have the leads attached and read 0V,there is no difference of electrical potential meaning there is actually 12V on both sides and the solenoid is not absorbing/using the power like it should be.If you simply read the 2 terminals on your battery it would read 12V,likely higher because a good battery will usually read close to 13V.A bad battery may read as high as 11.8V.As for the guages,it may also be that the battery is low if it has never been changed.The average life of an alkaline car battery is about 6 years.If yours was made and sold in 2000 like they like to do these days,the battery may have been changed once and is starting to be borderline.With the car off,no keys,nothing,read across your battery terminals and please let me know what you find. gmccarthy 86 hotmail
Greg

most likely a faulty alternator.
Good luck

hi this sounds like it will be your alternator if the light is still on after you have changed your battery, to test it source a volt meter, then with the engine idling connect to battery terminals it should read, 12 to 12.5v rev vehicle to 1000 rpm, it should then read 13.5 to 14v if not then this will be your problem the alternator is u/s...hope this helps

sounds like you have done more work than needed I wouldn't have changed your alternator, waste of money

1st check your battery with a multimeter (go digital if you can) theses are very cheap to buy, and you will use it a lot, set it to volts DC as per instructions start car and connect multimeter probes or clips to appropriate battery termianals, read display it shoud be 13.8 volts,, you now know battery cables and alternator are fine,, disconnect battery and do the same with multimeter on the battery again, leave sitting and watch reading if it goes below 12 volts over an hour your battery needs replacing.. If all good check when the battery terminals are back on tight and clean put the multimeter probes on termianls and ignition off and watch to see if reading starts to drop, if nothing turn ignition to accessories with everything turned off and again watch meter,, its a long process If you find it is still draining then pull a fuse at a time and check meter each time, if still dropping put the fuse back in and pull another one out.... repeat process till found........ before you start check glove box light isnt staying on, boot/trunk light is going off, ( put someone in there if you cant see) ,, If you have put in an aftermarket stero it may draw to much and you may have to upgrade your system, start with checking your battery

measure the battery when the car is off, it should read just a little over 12V. With the car running, measure the battery again and it should read between 13V-14V+-.2V.... odds are the voltage is below 13V if that's the warning you get and the alternator is not charging properly

hazard lights left on ? check to see waht relay it is that is clicking anr read to see what it is for? hope this helps

i would disconnect the battery again let it sit for 15 minutes, i changed an alternator and jumped the car then started driving and that happened to me, 20 minutes of driving and the computer finally kicked in and started working again. good luck