There are no 'pressure reducers' built in to the plumbing of these rigs. There are flow restrictors which makes less water come out of the various fixtures. You should be using a pressure regulator outside at the faucet you connect your hose to, as high pressure can damage your plumbing in the rig. The cheap 'regulators' don't work well, but an adjustable regulator will keep the pressure to a safe level.
Bob & Becky
2012 Chevy 2500HD D/A CC 4WD