A couple of things could be happening here, but check the 700/900 FAQ's.

The relays on the 700 series did not always have the best contact to the actual spade lugs in the sockets that make up the relay board. Solution was to remove the board, remove the spades from the sockets, clean the spades, resinsatll in the socket and make sure they were seated all the way to the front of the socket. Many skip the removal and cleaning part of the process and just push the female spades to the front of the socket. I personally would not do this because others have found faulty crips, detoriorated or broken wires from making too sharp a bend into the relay tray, etc.

That being said, there are two other possibilites; intermitent ground that is corrected by the "pushing" and a single relay, most likely the FI relay, that just needs a bit of jostling to get it going.

Try the first thing I mentione and see what happens. Then you can move on to other troubleshooting.

Onkel Udo