Hi. The bulb of the electro sends signal to turn on to 92nd and cuts to 87th, the thermostat starts to open at 87th. Then some controls would be established on the system and circuit of the electro, for example possible deficient contacts (rust and / or dirt, of the connector, in the same way of the respective relay, use clean contact spray and wiring). The system is reliable if the whole unit operates in time and form. In the same way the interior temperature indicator is not precise, for this a laser thermometer is used, you will obtain a reading of the real temperature of the motor and compare it with the first one. The correct and suggested is to maintain the originality of the factory. Salu2.