I am new to the list and an owner of a '83 240D. Love it, but am having some minor issues, including just replaced the thermostat. It's amazing how much better then engine runs when it is warmed up to 80C. Next up, my door locks.

I understand many things on a '83 240D work via vacuum. What is the LIKELY cause and solution to my door locks not working? Specifically, when I lock the car the locks do not lock. The lock problem arose gradually and is accompanied intermittently by the engine not shutting off when the key is turned to 'off'.

Doubtless this question has been covered in this or another forum, but I was unable to find such coverage based on a couple of searches. Thanks in advance for helpful suggestions, particularly where to look specfically for what I suspect may be vacuum leaks AT, IN, or NEAR the lock mechanisms in each door?

Best, Dan