Definitely call Lippert. I had the same problem. I called Lippert and they quickly sent out a replacement pump, with in depth R&R instructions, to my house. Took me less than 30 minutes to R&R.
'04 Wildcat 29BHBP (Sold)
'02 Chevy 2500HD 415k miles as of Dec-18
DMax/ZF-6 Speed, CCLB, 0-70-110 HP VA Tuner, 5" exhaust, H2 Tires/Chrome Wheels (315x70-17),
B&W GN hitch and 5th Wheel Companion, BrakeSmart Brake Controller