Central locking, relay or something else?

[MUNKSJOE]

Dear All,

My W211 E320 CDi 2003 has a fault that is annoying and getting louder. Every time I press the key fob remote to unlock the door there is a very loud electrical screech. When I lock the noise is the same but not so loud. The noise is much louder inside the car but I cannot pinpoint where the noise is coming from. Strangely if the boot is open when the fob is operated to lock or unlock the noise does not happen although the source of the screech does not seem to come from the boot area.

Any help/advise would be appreciated.

Regards

Alan

 

[John Laidlaw]

Could very well be the SBC pump which sadly is normal. Usually it’s more of a humming though.
Maybe if you can capture it, post up the noise and we can compare notes!

 

[MUNKSJOE]

Thanks for the feedback John. It is definitely not the SBC pump. The screech is within the car seating area and not under the bonnet or boot. I thought it might be a faulty relay, that is what it sounds like, but I understand that the relays are under the bonnet or in the boot.

Does anyone know where the central locking control unit is on a W211? This noise is getting so loud I am getting worried. Not too sure how to post the noise but I will try to find out as I need to get this problem solved.

 

[LostKiwi]

I wonder if it's a leaking hose from the PSE pump.

 

[MUNKSJOE]

Do you know where the PSE pump is located LostKiwi. I know it sounds strange that I cannot locate the position of the noise but it is multi directional but definitely within the cabin. I am willing to look at any possibility/suggestion so any help where these components are will enable me to eliminate them one at a time.

One other point. The central locking is working perfectly, its just this very loud screech is quite concerning. Has anyone else had this problem?

 

[LostKiwi]

PSE pump is normally in the boot. Either in the right side of the luggage bay or under the spare wheel or next to the spare wheel. It will have a stack of plastic tubes coming from it usually (but not always).

 

[robparker]

211 has electric locks and no pump. Each lock plugs into its door module and presumably sam controlled

 

[LostKiwi]

211 has electric locks and no pump. Each lock plugs into its door module and presumably sam controlled

Every days a school day! I thought all MB were vacuum/air.

 

[ajlsl600]

th

I wonder if it's a leaking hose from the PSE pump.

ere are some vac ,air pipes under seats .no?