If its a pre-mid 89 digi then according to the haynes manual there is a lift pump in the fuel tank with the gauge sender. To access it i think you need to lift the carpet and take it out from the top there. I'm going to have a look at mine over the next couple of days and check all the wires.
It does say from mid 89 onwards certain models had a single fuel pump, although doesn't say what models!