OK I did what men hate to do and read the directions
for your Paralax Power Components Model 3240. A few preliminaries however:
1. I see that they recommended series 7400, but I assume you want to use the older 32xx one that you already have so we will proceed under that assumption.
2. The blue wire I said goes to the brakes
is on the Scamp wiring diagram. The blue wire from your converter is the output and not what I was talking about.
3. You said that your 3400 has the relay feature (which should show as option C). You also say that it has the float feature which to me implies it has the optional battery charger built-in.
4. There is quite a bit more to consider than will be covered herein so be sure and be familiar with all the documentation for the unit, which I believe you can find here
under the Magnetek tab.
So the red wire goes to the battery (+) side, the blue wire goes to the “input” side of the fuse blocks (DC power distribution panel) which might be mounted on the converter or in a separate box). Yes, the colors will not match the trailer’s wires so be sure and check the polarity carefully. White is the ground (-) side.
Power will come from the battery or the converter depending on whether you are on shore (120 VAC) and go through the blue wire to the fuse block. The battery (+) might also be wired to the same "input" side of the fuse block. All the loads (lights, fans, etc.) should be wired to the other side of the fuses.
As for it being unfiltered, Parallax says this:
When 120 VAC is connected to Converter via commercial power of RV generator, Converter—via its Automatic Relay— [12 Volts DC from Power Converter] is instantly switched into the circuit to convert the 120 VAC to 12 VDC to run 12 volt lights and motors in RV. Equipment limited to operation from pure 12 volt battery power—including 12 volt TV’s, radios, stereos, unfiltered fluorescent lights—must be connected directly into RV storage battery line, or equipped with filter—as Converters do not produce the “pure” 12 volt DC needed by these items.
As I said before, mistakes can be very bad. One must really be “hands-on” with this to make sure it is done right so be sure of what you are doing or have someone who is qualified inspect it in person.