1997 GMC Suburban K1500 4X4 intermittent starting

When my truck does start I can hear the fuel pump working for a second, and the fuel pump relay clicks a few times. It starts, runs and drives with ease. Usually after sitting for a long period of time it fires up as usuall. I have noted when it won't start. This is when I turn the key to the on poss. I don't get a relay click, or fuel pump noise. I already replaced the ignition module, cap, rotor, plugs,
Is there a reason my fuel pump, and relay won't get a signal to engage?