I have isolated the drain battery drain to two fuses. Fuse C & Fuse 9.

I have removed almost everything that these fuses are asigned to, but am not sure where the central locking system is and what the relay comfort circuitry term. 86 rear door lock system or the seat back arrest are located. Can anyone help? It a 1992 300D sedan

My wife's 1992 300D has the same problem with a drain on the battery. Has anyone found an answer to this problem. The mechanic estimated 6+ hours to explore cause.

Looking for clues

Isn't the central locking air pump underneath the rear seat? Maybe its shorting out and keeps running.