W140 Vacuum supply line...need help! central locking

[plink49]

I have done all of the searches I can think of on this and cannot find an answer. The vacuum pump under the rear seat on my '92 500SEL eventually seized from constant running due to a leak (?). I recently replaced the pump but the leak is still there and I do not want the same failure to recur. The problem is on the clear tubing connected to "PU" on the distribution manifold of the pump, which I understand is the vacuum supply line from the engine. The line itself has a tag on it which is labled "DVS". I traced out the line to where it connects to yet another distribution point under a steel plate in the front passenger footwell. It is #6 on this unit. My question is where does it go from here, and what does it eventually connect to??