Hi, new to the site- I’ve just inherited a 2004 v70 with several issues, most of which have hopefully been resolved, but it seems to be a day to day thing.. the latest issue is the third brake light. It is staying on after the car is off. I can turn it off manually by unlocking the car and opening and closing the tailgate. IVe also been getting intermittent alarm service required alerts, and the moonroof suddenly is not working at all, not sure if these issues are related to the third brake light. But my main concern is not coming out to a dead battery. Any thoughts? Thanks in advance.

 

The backup battery in the alarm module goes bad, leaks and damages the circuit board in the module, the alarm module is after the sunroof module on the CAN bus and if there's a short or interference in the CAN bus signal (from the damaged alarm module) the sunroof won't work. You could disconnect the alarm module and that should make the sunroof work, but you will still get an alarm service message.

No clue on the center brake light - do the outside brake lights work normally? If so, there might be damaged wiring from the tailgate to the body where it has to twist whenever you open and close the tailgate.

 

Thanks for replying.. yes brake lights work properly, sometime it takes up 10+ times off opening and closing the tailgate to get the light to go off.