hey guys so I have a red light around my battery symbol, I replaced my battery, and I replaced the alternator with anything one from my parts cars, any ideas?? its a 1989 v.p xj40

 

Hi csperling,

Thank you for this additional information, but it may be more helpful if you can answer the questions we've already asked in the previous thread you started, and add this new information about the battery warning in that same thread. That way, we can try to help you diagnose your car's problems based on a comprehensive understanding of all the symptoms.

Thanks,

Don

 

csperling,

Verify if you have a load dump module installed. You'll need to remove the air filter assembly for best access, but easy to remove, see the pic for the part you are looking for. If you have one, follow the black lead over to the ground connection (near the headlamps) and remove the lead from the ground connection, clean and re-attach all of the grounds, except the one going to the load dump module.

Then start the car, wait a few seconds after starting and the red box should disappear. If that works (red box goes away), coil up the removed ground lead and tape (cover) the ground lug and secure it with a wire tie so it doesn't move around.

The problem is with the Zehner diodes inside the load dump module. The dump module has several functions, one to provide the reading to the dash of charge/no charge condition, another is to excite the alternator to output voltage, and to route extreme voltage spikes to ground to protect the system, but only if the battery cable becomes disconnected while the engine is running....so always ensure the battery cables are tightened on their posts.

Do not remove the module, it is needed for charging functionality, simply disconnect the ground lead.

First pic - load dump module installed
Second pic - module removed from it's fastening position
Third - module

 

hey guys this has really helped, I will look at the load dump, again thank you. now I have a bigger problems, so I replaced the alternator and the battery, and now my jaguar wont even start and it wont even turn over. I turn the key to the on position and all the lights come on, then I attempt to turn it over and the lights all shut off and it doesn't even make a noise no dead battery sound and no bad starter sounds, could you guys help me, I love my jaguar and I don't want to get ride of it.

 

My first thought is the linear gear shift switch. Be very deliberate in moving the gear selector in the Park position while observing your dash indicators and see if the Park indicator illuminates and extinguishes while you're moving the lever. If all indicators on the dash are illuminating, the switch is probably okay.

You'll need to retrace your steps on the alternator installation. Also, check both the negative and positive connections to the firewall to ensure they are clean and securely fastened.

Personally, I would put the old alternator back in with the new battery. Make sure the ground and the lead going to the load dump module are securely fastened to the back of the alternator, as well as the lead going to the starter. Before you put the old one in, remove the brush assembly and ensure the brushes move freely and are not restricted in movement in the assembly.

 

[QUOTE=Rob Evenson;1005093]csperling,

and remove the lead from the ground connection, clean and re-attach all of the grounds, except the one going to the load dump module.


The problem is with the Zehner diodes inside the load dump module. The dump module has several functions, one to provide the reading to the dash of charge/no charge condition, another is to excite the alternator to output voltage, and to route extreme voltage spikes to ground to protect the system, but only if the battery cable becomes disconnected while the engine is running....so always ensure the battery cables are tightened on their posts.

Do not remove the module, it is needed for charging functionality, simply disconnect the ground lead.



Rob.....I need some clarification......"similar issue"

Really , DO NOT reconnect the ground to the Load Dump????
....there are a lot of computers in our cars that are not front end protected for spikes.
AS you stated...to route extreme voltage spikes to ground .....
without the ground connected ,,,,,where and how can this module function happen???

also....What do you mean "the problem is with the Zener diodes??

 

[QUOTE=Greykitty;1010051]
Greykitty,

Yes, disconnect the black ground wire for the load dump module. I had a hard time buying into the concept myself, but I think it was Motorcarman that suggested (emphatically) the modification and it worked.

Further, I believe Motorcarman is a certified Jaguar repair technician and he was very confident the mod would cause no ill effect, and it has caused no issue thus far.

Remember, the ground is there in case the battery cable become disconnected while the engine is running. I can only assume that if a battery cable does come disconnected, the LDM will take the current from the alternator to ground. The only other connectivity for the LDM is to excite the generator (brown/black), and the other two leads are for the dash to provide status of the charging circuit. One lead to the dash indicator, the other to a fuse in the center fuse box.

The reference to the Zener diodes is research I did on the Jag-lovers forum where I found a thread posted by a guy that rebuilt the LDM and in the thread he stated the diode(s) blew out and he replaced them, and I'm assuming he had the ground wire connected after the repair. The thread was about ten years old and he was no longer active, so no means of contacting him for clarification.