im looking for the fuel pump relay

Under hood fuse - relay box .. Look under the fuse box 'lid' for fuse/relay identification... Also in owners manual .. IF you don't have an owners manual here is a link to a PDF manual for free; http://www.vadengmpp.com/owners-manual/gmc/1999-GMC-Sierra.pdf There is voltage to the pump for ONLY 2 seconds when key is turned on! .. I wonder how you have tested to confirm no power to fuel pump?? .. Anyway, good luck!