Remove/ install Coolant Temperature Sensor, but removing/ installing Coolant Temperature Sensor you have first to disconnect negative battery cable. Lose the cooling system until the coolant level goes down below the coolant sensor position. Loosen the electrical connector at the base of the sensor, and pull on it to remove the sensor from the engine. On some applications, the coolant sensor screws into the thermostat housing. Installation is the mirroring of the removal method, only in this instance it is carried out in the opposite order. This is to include procedures such as filling and bleeding of the cooling system. For the Oil Pressure Switch, loosen the negative battery terminal and the electrical connection from the oil pressure switch. Take off the oil pressure switch on the engine. Installation is done in the opposite manner of the removal process indicated above, the difference being that there is no need to wrap copper wires around a cable. Check the oil level.