Is this on your 2003 Pace Arrow?
If propane only then just one set of t-stats........
Normal temp (140*F) and an ECO (Energy Cut Off----Hi Temp 180*F)
If electric/propane unit your year model will have 2 sets of t-stats and electric set would be on backside of tank by element. Same temp settings.
Water not hot enough is usually cold water mixing with hot due to bypass valve being open or leaking thru.
T-stats not being held tight against tank wall usually results in VERY hot temp because t-stat is NOT sensing tank temp but cooler air temp so heating cycles last longer.
Might also check that outside shower (if applicable) is completely turned off via hot/cold handles vs shutoff on shower handle. Cold/hot mix inside faucet.