Hope someone can help.
I have a 1996..3.2..XJ6 Executive.
I'm having problems with battery drain, currently drawing 170 m/a.
Then if I remove the 10 amp fuse to the BPM it falls to 40 m/a which I believe is acceptable.
What I'd like to know is there any other circuit ie: interior lights..windows seats ect that could be causing this draw on the BPM or would it need replacing.
Also if I fitted a battery isolation switch and used it daily would it cause any damage to the electrical system.


Any help really appreciated.......Thank you...John.

 

John,

I've moved your question from XJ XJ6 / XJ8 / XJR ( X350 & X358 ) to X300 forum. Members here with the same model will be able to help.

Graham

 

Hi John,

Welcome to the Jaguar Forums! It's great to have you with us.

You might take a look at this current thread, since it has some relevant info about diagnosing excessive current drain:

https://www.jaguarforums.com/forum/x...attery-140172/


Also, you can download the 1996 Electrical Guide at the link below to review all the circuits the BPM is involved in:

http://www.jagrepair.com/images/Auto.../jagxj1996.pdf


Please keep us informed.

Cheers,

Don

 

Hiya Don and thanks for your advice.


I'm a fridge engineer who's electrical experience is limited to single phase/three phase systems, unfortunately I haven't a clew when it comes to anything 12 volt the amperage frightens the life out of me.
What I've decided however is to live with this 170 m/a drain as its only a 2 watt draw.
I think the best thing to do is to attach a 100 amp isolation switch to the battery so I can isolate it if I need to leave the car for a few days, I drive drive daily at present approximately 30 mile so this new 91 amp battery I've bought should at least keep it topped up.


Thanks again Don and I really appreciate the wiring diagram.


John...(John the Fridge)

 

The battery in my '95 XJR was going flat after about a week. I found a small current drain similar to what you found. It was through the BCM also. To make a long search and testing story short, what I found was that the switch in the ignition switch which detected whether the key was in or out of the lock, was sticking. There was no obvious indication of this such as the door open, key in lock, "gong" sounding.

Before replacing the entire ignition switch, I squirted some lock oil (I used TriFlow) into the ignition lock and exercised the lock by putting the key in and out many times. Then I gave the oil time to penetrate overnight and Voila!!, the battery drain disappeared. It has been over a year now with no problems.
I also had the same problem in my '93 Volvo 940 but, in that case, I had to replace the ignition switch.

 

Thanks for that mate.
I'll spray some WD40 into the lock and see if it clears the problem.
It's a nightmare trying to route problems with the BPM as there's so many reliant circuits involved.


Anyway thanks again....John the Fridge.

 

Hey Fridge
I had my car (X300 XJR) out of service for ages so had the charger connected to the battery, regulated at 13.6V. Of course the boot (trunk) was open for this so I pulled out the boot lid bulbs (globes) as they would have been lit.
Despite removing the bulbs I found that there was about 150mA flowing to the BPM vie F5 in the boot. I spent a lot of time trying to find out where this was going. I even pulled individual wires one at a time from a BPM connector but no one wire reduced the current drain significantly.
I had assumed that having the boot open would not cause any current drain because I had removed the bulbs, but after all my fruitless effort to locate the current drain, in desperation I moved the ammeter outside the boot and closed the lid, and what do you know, the current disappeared!
A small current flows into the BPM if a door is opened too, so I guess that this is the current drawn by the BPM door/boot status-sensing circuitry.
The boot lid open/closed sensor switch is in the latch mechanism, so if you simulate closing the boot by pushing something into the latch you can measure the change without actually shutting the boot. Of course , you will then need to "open" the catch before you can physically close the boot.
Anyway, measure battery drain with the doors and boot closed!