My heater blowers dont work, if i bypass relay 6 & 7 they come into life.

I have traced it down the the negative feed not energising the 2 relay, I believe this feed comes from the becm, is this correct?

The fusebox is not at fault as i have checked the negative input into the fuse box and get the same.

If there was a heater fault would the hevac shut the negative feed down?