Probably have a SHURFLO RV Pump which is a part of the Pentair Inc.
BYPASS Pump would mean a 4008 Revolution (Internal bypass type pump)
You need to check the valving on your water heater (backside of tank)
Cold water inlet (bottom) OPEN
Hot water outlet (top) OPEN -----if you have a valve and not just a 'check valve' in nipple on tank
BYPASS valve (connects cold to hot) CLOSED
Verify that water heater is full of water (pop open T&P Relief Valve CAUTION: IF water has been heated it will be scalding hot)
With water supply ON
Open faucet closest to water heater....hot side
Does it run hot water, warm water and then goes cold? BYPASS VALVE is leaking thru OR is Open (cold water is mixing with hot water)
Look inside cabinet/drawer for a 'info sheet' that lists items in trailer.
Which Brand/Model of water heater.....Suburban (SW6A-7E etc) or Atwood G6AA-7E etc) OR look in water heater outside compartment for info)?????
Faulty t-stats either mean COLD water cause they aren't working OR VERY HOT water cause they didn't shut down
WARM water is cause of cold/hot mixing