2007 2.0l 520D M Sport Touring Remote Locking Help!

[gadgetmanjat]

Hi, just bought this car and the seller said the remotes had ‘just’ stopped working. This is a push start ignition with inserted key fob type.

I have to unlock the door with the key part and quickly push the fob into the ignition slot to stop the alarm.

He hasn’t driven it for a while. I’ve opened up the Diversity Antenna awas bone dry, no moisture or corrosion marks. I have two remotes that are sealed type with no battery replacement port, so assume they are ‘rechargeable’ type.

My thoughts;
+ Without spending £250 to replace the diversity antenna, how can i determine if it’s that or a remote fault?
+ Neither remote works, but assuming they are discharged, how do I charge them outside of the car? I’m only commuting for 30-40minutes each way on a daily basis and no plans for a long trip and I’ve read it could take 10+ hours to charge them?
+ I’ve checked what I assume are the correct fuses but if anyone can confirm which fuses I should have checked, please?
+ I’ve read about re-syncing keys, but no idea if it’s worked!
+ what ‘should’ I do?

Thanks in advance!

[Huskyman]

You can change the battery in the keyfob, they are not sealed, and are of a similar style to the E90 key fob. Try a new battery and go from there

[AW10]

Does the car have a panoramic sunroof? If yes check the spare wheel well under the boot floor for water ingress. And even if it doesn't have the pano roof check anyway. There are several control modules cleverly located at the bottom and they don't like water. Any other electrical glitches?

[Elliot2000]

E90 and e60 style keys are sealed unless comfort access was selected as an option on the car from new.

U can bodge a battery into them but it’s not brilliant and probably not it issue.

If u take your diversity module apart (it’s only clipped together) then check the earthing points for corrosion - it may have been wet in the past but now dried up.

The other common thing is a wire breaking in the loom for the tailgate above the roof lining- if u have the speakers in the roof just pop them out and check from there, if not, lower the roof lining at the back and check them