Hello,

Occasionally, in the winter weather, the vacuum pump under the right side of the back seat runs for about 10 to 15 seconds after I unlock or lock the doors via key or internal door lock pin.

If this happens, the doors are very hard (hard to push pin or hard to turn key) to unlock or lock and only the door you are working with will do the lock or unlock action.

After the sound goes away, (the pump stop pumping), everything is normal again.

I am looking to install a keyless entry system on my car and want to make sure this problem is taken care of first.

Any suggestions on where to look?

__________________
2006 BMW M5 "Heidi" @ 109,000 miles
2005 MBZ C55 AMG "Lorelai" @ 165,000 miles
1991 MBZ 300E "Benzachino II" @ 165,000 miles
1990 MBZ 500SL "Shoshanna" @ 118,000 miles

(On the hunt for a good used M103 engine as of 6/10/23, PM me if you have one to sell!)