Yeah, my father in-law did it on my 280e. I'm not exactly sure how he did it, but I think he attached a timer\relay thingy to the pump. It is then activated by the lock\unlock of a remote control central locking unit we installed, telling the pump to run for 5-10 secs (enough time for doors to lock\unlock).
Email me if your interested and I'll see if I can get my father-in-law to sketch out the exact details.
Steve
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