My Mercedes acts like this with strange lights turning on, like tail lights, etc. The cause for the Mercedes is usually water under the back seat where there are some electronics. Water is from a window being open or the door ajar during a rainstorm. (I have kids...)


So if your battery is good, maybe look for water intrusion somewhere.

 

Nope, they were on auto. It was raining the last couple of days so hadn't driven or done anything with the car since Monday, and Thursday morning was when I found the lights on.

There has to have been something else then. My CTEK went through the full reconditioning program overnight, and the battery is staying at 11.9. Will take the battery back to Sears (assuming they're still around), and see what they say since the battery's only a couple months old.

 

Yea sounds like a defective battery. The AGM should hold up well in the conditions you described. I'm sure Sears will warranty it.

 

11.9 sounds like you have a bad cell.

 

I'm not suggesting it's your module, just from experience that a dodgy battery after putting the roof up or down a few times can leave insufficient charge to start the car.
That's what happened with mine. New battery sorted it.

The module itself is great.

 

This might be the route I have to go for now. Thanks!

 

Simon,
I experienced headlights going on by themselves for no apparent reason.This of course would cause your battery to drain. Please read my earlier post. Dealer action resolved the problem.

https://www.jaguarforums.com/forum/x...ar-off-168512/