Without looking at a manaual Im not sure which is the fuel pump relay so I cant speak to that at the moment. But after charging the battery or after a good drive where it will come up to 14.3ish volts it would normally settle down to 12.6 volts. Occasionally checking with a digital volt meter after sitting for a couple days It shouldent drop below that by much if things are normal. if you pull that relay your battery voltage should maintain the 12.6ish volts. I suppose another quicker way would be to get the battery charged,turn off everything,engine,key,ect,ect and pull each relay under the cover one at a time. If one is hung up you will feel/hear it click as the contacts open. Relays do get stuck sometimes,just ask a durango or Chysler mini van owner. Unforunatly in their case the entire fuse box needs to be removed and a new relay soldered in or the entrire fust panel replaced. Another brilliant engineering feat from DC.