New RVer with some diesel fuel issues.

You stated you have a 2005 Meridian 39f. You didn't say which engine you have. My Meridian 39K has a Cat. It has the fuel filter/water separator in the rear compartment where you can check the oil and water level. It has another fuel filter located on the engine, passenger side, towards the front of the engine, under the intake manifold. All these directions reference sitting in the drivers seat facing forward. Now the fun. To access the fuel filter on the engine, you must remove the steps at the foot of the bed. There are 4 screws holding the cover/steps in place. Once the steps are removed you can locate the secondary filter. I installed the Cat mechanical priming pump when I first changed my secondary fuel filter. If your motor is a Cat, call Cat with your engine serial number and they can provide you with the proper fuel filter.