OK I've had a look into this, and it appears that your connections, in theory, should be OK.

In the 5 pin plug, you need 3 wires as follows :
a brown/yellow feeding ignition-switched 12V to the connector
a brown wire to earth
a brown/black from a relay (pin 85) that switches the pump feed (87 & 30) (pin 86 will be another ignition-switched feed)

The wire colours listed above are the original colours, and obviously yours may have been changed, but you should be able to use the above info to check, for example, if your relay is sticking, or if the wires have melted together, etc.