For the second time this morning, I'll say that every W123 should come with a MityVac as standard equipment.
If you really don't want to mess with the vacuum door locks, lift the carpet out on both sides in the front, and look under the plastic channels. There you will find the vacuum lines joined by rubber connectors. Just pull all of them apart. Then go into the engine bay, pull the yellow vacuum lines out of their connectors, and plug the connectors (on the brake booster side) with golf tees.
The green vacuum line is for the climate control system, which could also be leaking.
For the dash lighting, pull the cluster out and check the rheostat. The springs are known to break, leaving you with no light. Some people just pull the rheostat altogether and wire the two posts together.
Somebody is sure to complain about the fact that I told you to destroy the lock system instead of fix it, which is relatively easy. But when I buy those cars from you, I'll put them back together properly.
