Hi there,

I was hoping to get some expert advise on the probs with my 94 C180 W202.

After a lot of reading in the forum, I think I might have a burnt out PSE pump, but I need some confirmation before I go out and buy another one, which is not cheap! .

Here is some background, which indicates that it has to do with the vacuum system in my car.

1) The centre a/c vents doesn't work and it hasn't been working for a while. Air only comes out from the side vents.

2) Until about 1 month ago, the central locking stopped working.

3) Up until 1 month ago, I can hear a 'whirlling' coming out from the PSE pump, that turns on/off every few seconds. It only happens when I have the ignition key in the ON position (not starting the car). Once the car starts, its goes away.
At the same time the central locking wasn't working, the noise (intermittend pumping noise) went away.

At present, when I turn the ignition key to the ON position, I don't have any noise coming from the PSE pump. I located the PSE pump and remove the ZV hose (yellow) on the PSE pump, which I presume controls the Central locks. With the hose remove and the ignition in the ON position, the pump does not do anything. It doesn't turn on/off anymore. Does that mean the pump is burnt out?.

How can you tell if the PSE pump is working or not?.

Also, I been told that even if i replace the PSE pump, I will need to track down all the vacuum leaks, because if not, it will cause the new pump to burn out as well in the long run....

Dilemma is, because the PSE pump is not working, I have no idea how to find the leaks, or do I have to put in a new pump in first?.



Any suggestion?

Thanks in advance