86 560SEL fuel pump relay going bad??

[rsmartin]

this morning my car wouldn't start. turned key, all the idiot lights on, car turned over but wouldn't start. turned off, turned key on again, noticed i didn't hear the fuel pumps run when i turned the key as they always buzz for a second when i first turn the key on.

so i turn to my trusty MB CD and look up fuel electrics. check all fuses, none blown. so pull all three relays that are between the firewall and the engine wall (whatever that's called). gave them a shake and a few taps and put them back in again.

turned key on and still not fuel pump sound. turned key on again, and this time hear the usual buzz. turn key to start and motor fires right up

so now i'm wondering... which of the two black relays is the fuel pump relay. the one closest to the center of the car? or the second closest to the center?

AND.. is this thing going to fail while i'm driving. Friday, as i was driving out of my drive way, the car shut off twice. it started right back up each time, but shut off twice in a row like that. it's never done that before.