Camping World has a deal on the HWH AP1111 Control box for Computer-Controlled Hydraulic Leveling System ($99.93 vs. $608.79). Although the Camping World ad references Newmar, I saw an IRV2 post referencing this in conjunction with an HWH 610 system on a '99 Winnebago Class A.
Even if your's is OK, if your rig uses this, it might be good insurance to buy one just in case.