Well, each of them has a single wire which runs in the harness that crosses over the top of the engine in front and they both only have one connector. If he had to pull the harness out of the way (can't why he'd need to) he could have accidentally pulled them loose... OR if the insulation is bad moving the harness may have just expedited a job which was already in progress and created a short in each line. Just start with checking the connection on the sensor which runs to the thermostat neck (but isn't in the thermostat housing with the others) and wiggle the wire harness a bit. These I suspect you should be able to do yourself, reaching the oil pressure sender is a pain.
http://www.toyota-supra.info/forums/49475-post2.html