Something is really amiss in the OP's unit or at Thor. My 2008 F-Super Duty Class A Motorhome Chassis INCOMPLETE VEHICLE MANUAL clearly states in the "Statements of Conformity" Standard 105 'This vehicle when completed, will conform to Standard 105, Hydraulic Brake Systems, if:
• No alterations, modifications, or replacements are made to the following:
– Service or parking brake system
– Antilock brake system
– Wheels and tires
– Brake system indicator lamp and wiring
– Brake system reservoir labeling
– Suspension ride height or spring rate
– Hydro-boost or Hydro-max system
– Power steering pump and lines
– Engine Belt Drive System
When looking at my chassis wiring diagram, the hydro-boost pump is powered directly from the engine battery junction box via a 60A fuse. There are no disconnect power relays in the line.
How anyone could modify/defeat the Hydro-boost system and ASSUMED it still complied with the standard, borders on criminal culpability. JM2¢...
