Lifetime Premium Member
Date registered: Oct 2002
Vehicle: 1967 250 SL, 1963 220Sb
Location: Los Angeles / Altadena
Mentioned: 3 Post(s)
Quoted: 102 Post(s)
Go buy a mitivac tool first of all. The kind that lets you pump and read vacuum. Get a vacuum diagram of your car. If it's the same as W123, yellow w/ red stripe is the locking circuit, yellow with green stripe is the unlocking circuit. If it's like a W123 you can test at the junctions under the carpet rather than test the things in the door.
In my 123 wagon I ended up replacing the tailgate actuator and two door actuators. Note that they can leak in on direction only -- holds vacuum for locking but not unlocking for instance so you need to test both.
Currently: 1967 250 SL, 1963 220Sb, 1965 300SE Lang, 1971 280SE parts car, 1972 Alfa GTV, 1965 Alfa Duetto, 1993 BMW R100R
Past: 1971 250 C, 1985 300 TD, 1967 250 S, 1968 280 S,1981 300 D, 1982 280CE, 3 Facel Vegas, Borgward Isabella Coupe, Alfa 2600 Sprint, Volvo P1900 (yes), numerous less interesting Volvos, ...