8-88 F350 7.3 automatic blowing fuse randomly

[STWTAHH]

Gentlemen, I am new to this forum. It is awesome. I have looked all over this site and hope I am not addressing a dead horse here but I have a problem I need help with.
F350 incomplete chassis built 8-88 7.3 automatic. It randomly blows the gpr circuit fuse, had a new relay installed before I started working on it. I'll post fuse # when I look again but I have a 30 amp breaker in it right now and it runs fine but randomly will trip the breaker and shut down. Wait a bit and runs again sometimes the rest of the day no problem, other times it does it every 100' or so, 3-4-5 times then it's good for hours or days. Does not look to have the fuel heater in the filter housing I have read about...It has 1 wire to top of filter housing I assume is water in fuel sensor??? Checked a lot of wiring and have not found anything terrible and what I have fixed hasn't cured it. Any help is greatly appreciated and will give info as needed. THANKS guys!!!!

[powerstrokemonster]

the 1 wire plug in top of the filter housing is a fuel heater. but if have already replaced the relay i would check the wiring going to it for chaffing and grounding that causes it to trip good luck