Hi guys

I've been having a few probs with the coz of late I seem to get over 1 prob then another arises!!!! This time it's relays!!!!
I've put a new fuel pump wiring lume on from MSD followed the instructions & it works a treat the all of a sudden it keep blowing the relay next to the battery & not the fuse????? Then the other day it did both of them????? Can't get me head round this
As soon as I replace witch ever 1 has gone its fine & it's not all of the time?
Cheers in advance for any help.