I think it's safe to assume that of them was always emitting because it's working now without opening it. Something was interfering with the whole thing those few days.

Replaced both batteries recently on same time, and the sync worked for both in a row. The solders are good in the faulty one. But with 1.5v no wonder it wasn't syncing properly.

At first thought it did not occur to me that the almost new battery already passed out, so forgot to mention that detail. Can happen with aftermarket items i guess.

__________________
E53 - 2005 3.0dA