aka Pre-glow time relay This control unit is located under the battery tray.
This unit is manufactured in Germany by Wehrleh an OEM automotive parts supplier to Mercedes.
This is NOT a Chinese knock-off part, as often seen on some other sites online.
This is the newest (third revision) and most current version of this unit. It is considerably smaller than the earlier unit and has automatic circuit breaker type reset, unlike the first units that came with the vehicles, when new.
The original units had internal fusible links that would burn out and the entire unit had to be replaced.