I have a 1996 C280 that has a vacuum pump by the right rear of the car that runs every 15 seconds of so when the air conditioning fan is on. A/C or EC doesn't make any difference.

I know from other posts that there is a vacuum leak somewhere under the dash in the vacuum actuator or the vacuum servos.

My question is how do you unplug the lines to test the vacuum coming out of the actuator? This seems like the logical place to start. The hoses are plugged into couplers that are ribbed making it very difficult to pull off.

Does the vacuum actuator crap out and leak itself often?