Hello. My uncle has a 2008 XF that has just recently developed a few electrical problems.

The cental locking no longer works
The entertainment system will not boot up it cycles the Jaguar logo but never comes on
Electric windows do not work.
Key fob has to be placed in the recess under the stearing wheel to start the car. My understanding is the car should be able to start with the key close to the dash?

I thought it could be a problem with the Bluetooth module under the passengers seat (left) but the fibre optic cable shows a flashing red light which I am led to believe means it is getting power. I then went to the boot and unplugged the modules one by one. The only module without a steady blinnking red light is the SatNav module but according to my Uncle that has never worked since he bought the car 2nd hand about a year ago so I dont see how that could be causing the Entertainment system to boot loop all of a sudden. I actually tried the Fibre Optic bypass using a cable bought online to see if I could rule out any modules but as they all seemed to be getting power it didnt work. Any help is greatly appreciated

 

The boot cycling could be a bad module in the fiber loop eg the BT one. It may be getting signal but could still be faulty. Sounds like you tried bypassing each module?

Have you pulled the error codes? What comes up / that might give us some clues

And someone will ask - how new is the battery and is it well charged? No.1 issue with electrical gremlins is a weak / undercharged battery. What's the voltage across the battery terminals when engine is off

 

I did try to bypass each module. The BT module under the seat had another smaller module nexrt to it. No idea what it is but I tried bypassing that to. No EML light on the dash although Im not sure it would show on even if there where error codes. I do have a cheap OBDII bluetooth dongle but I never tried that. Not sure if it would work anyway? I think he has had battery problems but I cant remember if he says it has been changed or not. I will ask tomorrow. Thanks for the reply

 

You need to get a volt meter across the battery, how many volts with the car off & when the engine running! I have this fitted into the boot/trunk

 

Apparently the battery has been tested and is OK?

 

I also run a volt meter and it's way easier to get a cigarette lighter version with 2 USB ports for charging. This is much better than installing something in the trunk where you can't see it. Now I can open my center console at any time and see;

1. If the car is "alive" at all
2. What voltage I have when the car is sitting.
3. Running voltage to check the alternator output.

Only about $8 on EBay too.


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Think the other module is the Sirius radio one, but not sure

I would measure battery actual voltage when engine is off first to eliminate that. FWIW I had a new battery that tested fine at the shop but wouldn't get to full charge. They swapped it on warranty and was perfect after that.

You only get a CEL light for serious engine issues. There are many more codes that would be helpful that you can pull with a good reader or have an auto shop do for free

I'd suggest posting back up here battery voltage and any codes and we can look at what you find