TexasBuckeye

I don't have the 400, I have a 550. I am assuming it probably has the same interlocks, but is it possible you don't have your driver side seatbelt latched or that the contact is not changing state when you do? The wiring can be accessed in the engine compartment right behind the driver seat where there is a cable connection and you can check it (you are checking the cable from the seatbelt). The contact is closed when the seatbelt is not latched, and the contact is open the seatbelt is latched. You can disconnect the cable (bypassing the interlock) to see if that makes a difference.

I ordered remote control hardware from Amazon https://www.amazon.com/dp/B07P2G4T22?psc=1&ref=ppx_yo2ov_dt_b_product_details and initially installed module behind the switch panel and wired it into the winch control switch. After researching the 2014 HiSun service manual posted by another forum member, I discovered a better way to implement (fyi-this is not documented any Coleman service manual that I could find) My UTV is a 2022 model, but the wiring appeared to be the same for my model. There was an unconnected Molex plug hanging under hood on the driver side (Molex#33471-3301), (see photo). I purchased a Molex 3 wire connector ((Molex#216283-1032) directly from Molex for $5.82 including tax & shipping. This connector has the 3 wire pigtail to easily splice to the remote control module wiring. https://www.molex.com/molex/products/part-detail/cable_assemblies/2162831032 . I added a ground stud near the parking brake mechanism in order to connect the black wire from the module see photo) . I added velcro to the module and then secured with zip ties to the back of the nameplate bracket (see photo). See the wiring diagram for hook-up that I used. The loose blue wire is the antenna so it is not connected to anything. Molex Wiring.pdf

Similar issue on my 2022 Coleman Outfitter 550 where the parking brake was locked up.....parking brake pedal would not automatically release when applying brake. I had to adjust the tension on the cable release that runs from the brake to the parking brake pedal (located on the other side of the floor panel behind the parking brake). I then adjusted the parking brake pads per the procedure mentioned previously. If you can't easily push utv with the parking brake disengaged-you know you have a problem. By the same token, if you can push the utv with the parking brake engaged-you also have a problem.

You probably already resolved this issue, but if not or for the benefit of others I have attached image that shows the location/installation of the fuel filter. In this case, it is a Coleman Outfitter 550 and the filter is under the passenger seat.