I recently bought a 2004 jaguar xj8, everything was working fine up until a couple days ago. The headlights/high beams won't turn on, front turn signals won't go on (all rear lights work fine), the windows won't roll down (all the switches won't do anything), the glove compartment won't open, the gas cap lid won't open, and the sun roof won't open. Also, the trunk opens but only with the fob and the button on the the trunk itself, the button next to the steering wheel doesn't open it. This all happened at once while just a day or two ago everything worked perfectly. Any suggestions?

 

Sorry to here about this. I imagine it was quite alarming when this happened. Your symptoms are consistent with a grounding Issue. I would first do a search on this forum for cleaning the ground points on the x350 and follow the instructions and see if that helps. Good luck!

 

Actually, I would first check that your battery is good and the proceed with cleaning the grounds.

 

I unhooked the battery and everything turned back on. I just wish I knew what caused it in the first place. But I'll clean the leads like you suggested

 

For any electrical fault the FIRST suspect is the battery or its connections. The various modules in modern cars need full battery voltage all the time. Your symptoms are classic signs of a battery either faulty, aged or simply not at full charge. A car that is used infrequently or even frequently for short runs will eventually have a battery below full charge and the sort of symptoms you describe will appear (and there are others...it can be anything, warning lights, touch screen malfunctioning....
By disconnecting the battery you did a hard reset of all the modules; this procedure is essentially similar to rebooting your computer if there is a fault and it very often cures the problem...but the battery remains the prime suspect.

 

A word of caution cleaning the grounds.

The bolts can break the mounting quite easily if you are not careful.

 

almost guaranteed

drill new holes and use bolts

 

Since you said that the car was recently purchased, Usually when someone sell this type of vehicle, they use to had it parked for a while, wether they don't use it that much or whatever reason, so the first thing to check out is the battery. That happened to me and many others after a few days of the purchase of the vehicle.

 

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