The Frigidaire model LTF2140ESO is a front-loading washing machine. Since the loading door is in front rather than on top, it has a latch safety switch that locks the door and prevents it from opening while a wash cycle is running. For safety reasons, if the switch fails, the washer will not lock the door, nor will it allow a wash cycle to start. The switch can be easily replaced with just a few tools.
Unplug the electrical cord from the wall outlet.
Open the loading door. Gently grab the boot seal retaining clamp, using a pair of needle-nose pliers. Pull the retaining clamp off of the boot seal. Do not pull too hard as the spring can stretch and deform.
Locate the latch switch to the right of the boot seal. Gently pull away the boot seal near the latch, just enough to get a hand through.
Remove the two latch switch assembly retaining screws, using a Phillips screwdriver. Pull the latch switch assembly out of its mounting holes and past the boot seal so you can access the switch's wires. Be careful to not tear the boot seal with the sharp edges of the latch assembly.
Disconnect the latch switch assembly's wiring connectors, then remove the assembly.
Install the new latch switch assembly and wires. Secure the latch assembly, using the two Phillips screws.
Push the boot seal back into position, over the front panel's flange. Reinstall the boot seal clamp over the boot seal. Be sure the clamp's spring is behind the front face of the boot seal.
Plug the washer into the electrical outlet and run a test cycle.