My ultra reliable 280SL inexplicably wouldn't fire after sitting about an hour . Soon realized the pump wasn't running. Aha, I thought, in my usual know-it-all fashion, fuse or holder - Ha. Well, after a bit of checking, found no voltage at the pump.
Suddenly, again inexplicably, the pump was running. Drove app. 30 miles home without incident. Left it for a while - then, no pump ! Well, hair pulling, long story short, finally found the problem to be the rear lights harness multi plug to be the fault. This is in a wonderfully hidden position to the left of the other fully accessible multi plugs below the dash !! Turned out the female section of the pump connection had opened up slightly over the years. Gentle squeeze, applied di-electric grease - problem solved. Not suggesting this to be a common fault, but hope it may help someone in the future.
