My son reported to me that the trunk on his ole '87 300D will not open. He can use the key and try to turn it but it will not open. Normally he opens the doors and then goes to the trunk and can open it. The familiar "thunk" sound of the vacuum locks. Well he says it sounds like it tries to open the lock but it still will not open.

He can open and close the door locks no problem so there is enough vacuum in the reservoir. I had to trim his door lock button a few months back. Someone had un-screwed the **** and in the process the bottom of it was all deformed. After trimming the deformed piece off he reported the door locks were working great and much better than they had ever worked for him. I suspect the door valve for the rest of the locks was only partially engaging due to the **** being boogered! Well in the time frame prior to the fix for his door locks the trunk would act like this. Unable to open the thing.

Now I am a bit perplexed. The doors work fine but now the trunk is still acting up. Any good suggestions?

 

Sounds like the trunk vacuum switch is going bad.