Ford 5000, Kubota 2150 HST, NH TC45 D, JD 375 Baby Skid Steer --- STUFF THAT GOES ON EM, Schwinn Stingray
If you have a broken wire to the switch where you tie all (both) the wires together makes a difference. It doesn't do any good to tie them together at the switch if the wire is broken.
A lot depends if it is a NO or NC circuit.
NO going to ground would be the easiest. Short feed to ground or connect the two leads together.
(Naturally it is assumed that you are doing this for test purposes only.)
On mine the switch had a male and female so I simply join them to bypass and taking them apart acts like a kill switch to fool thieves. My circuit is a NC one. (none on my seat, only a neutral position for starting)
If your worried about safety, Wire in a toggle switch under the seat rather than the pressure sensor. Otherwise scrap the pressure switch. It should be a positive wire , when you sit on the seat the switch activates and current flows through the other wire.