For those that run into a 4x4 or locker switch that gets stuck or won't stay in. I have found that on one of my 2019 CF moto400S, the 4x4 switch, which is the same as the one in the SxS, would not stay in when trying to engage it.
I opened it up and found that the grease that was in there simply dried out. I had a packet of the Spark Plug Dielectric grease you can pick up at the auto parts store and re-greased it.
If on an atv, you don't need to unplug the switch, you can just open it up.
1. What you do is, remove the two screws to pull the switch body from the housing.
2. Then you will see two screws holding the circuit board to the plastic button housing.
NOTE: Hold pressure with fingers on circuit board, pushing down, while removing the screws with the other hand.
3. There are springs inside and they may pop out so open it slowly, do NOT turn it upside down.
4. Once you have it opened, you will see two springs at the back of each switch, I used a small pick tool but a small flat head would work to pull the two springs out.
5. Now this part is a little tedious, you need to lift the white block straight up off the button. The button shaft has two grooves that the block slides over, be careful the silver contacts are just sitting in there, and under them is springs and a pin, if you turn it over they will all fall out. A small pick tool works good for this, just be patient as you do it.
6. once the block is out, you will see a white plastic guide with a triangle slot in it, note the back has a plastic pin that aligns into the hole in the back of the housing.
7. smear the grease under this block.
8. put the block back down and make sure the little plastic pin is in in the oval hole
9. Smear a little grease on the top of the block
10. when you pickup the contact block to put it back in, verify the metal pin is sticking out, you can push on the contact and it should pop through.
11. Put the contact pin into the housing, make sure the block goes over the button shaft groove.
12. Once the block is in, carefully put the spring in behind it.
13. Once both blocks are in, smear some dielectric grease across the contacts and block tops
12. Put the cover back on slowly and once it is on, pinch it down and hold pressure until you get at least one screw in.
13. once you get both screws in, you will need to cycle the switch a few times to get it to start functioning properly.
14. once you are happy with the switch function you can put it back in the housing on the handle bar.
Generally i find after a few cycles it will be smooth again and the buttons won't stick anymore. I am assuming that with my ATV's out in the sun under the cover caused the factory grease to dry out, not really sure, but it was bone dry.
NOTE: For $15.00 you can buy the switch from VMC, but if you have 2018 up the connectors are actually different so you just need to splice it on. I did purchase them just in case and they arrived very quickly.