fuel pump problems, again

the "trusty" jeep has been fighting me ever since i moved out here it seems. as some of you might recall, i put a junkyard tank in it and just before christmas i put a brand new fuel pump and sending unit assembly into it form advance auot parts. since then shes run great, but in the last few weeks with it being warmer, theres mud around here now. every time i play in some (talkin at least a foot of water and mud) the fuel pump gives me problems the next day. last time it was blown suppy fuse. this time i dont kno what. fuses and relay good, connectors clean and hooked up, even fuel gauge reads, but the pump wont turn on. 99 XJ, 4.0, auto

Did you check all the grounds inside the tank? I'm not sure about how the 99 tanks are but on my '91, the ground for the pump runs up the return tube on the pump assembly. The little weld holding the tubes in place broke, which basically made for a crappy ground that wasn't reliable at all. I went through 3-4 fuel pumps before I found the problem.

That pump you installed wouldn't happen to be a MASTER unit is it?

When you pump fuel out, air must go in. Has the mud pluged your tank vent?

Sounds to me thats whats happning.

yeah it is a master but i havent had any problems til now. i gotta borrow my buddys DVOM and get under there and see if itys gettin power and such