I'm having some problems working out why I'm not getting a power supply to my fuel pump. Any suggestions on what to check would be very welcome!
So far I've checked the fuse (No. 23, as well as all the others), switched the fuel pump relay, switched the main relay and even switched the motronic ECU with a spare I have. No of these have made any difference.
I've checked the fuel pump itself isn't faulty (took it out of the tank and hooked it up to a battery directly - works fine!).
I also checked that the fuel lines are clear, not that this would have any effect on the power supply to the pump, but may have been the source of the problem.

I can't think of anything else to check!
Please help!

1989, 520i 12v auto
247,000 miles!