I finally found out that the OEM iPod kit that one of the previous owners installed is causing a slight key off battery drain, approx. 100 mA.
http://www.mercupgrades.com/IPOD+Retrofit+in+E++CLS+Class-article-62.html
If I pull out the grey relay (see picture in above guide) I can see a drop of approx. 100 mA. When I reinstall the relay I hear a click and the drain is back. Also I note the relay is warm to the touch compared to the other relays.
http://www.mercupgrades.com/IPOD+Retrofit+in+E++CLS+Class-article-62.html
If I pull out the grey relay (see picture in above guide) I can see a drop of approx. 100 mA. When I reinstall the relay I hear a click and the drain is back. Also I note the relay is warm to the touch compared to the other relays.
- I have tried a brand new relay from Mercedes, this made no difference, same symptoms as above
- I have tried disconnecting the iPod black box which is located under the glove box, no drop, continues to drain
- I have tried disconnecting the aftermarket bluetooth module which is connected to the iPod kit, no drop, continues to drain