Are there any lights lit on the front of the TV? Have you checked for a bad lamp? When you reset the TV the timer/power light should flash on and off rapidly for 60-70 sseconds. Does that happen?
The sensor is usually right by the lamp, somewhere by the housing. There were a few bad batches of temp sensors and some others where the temp sensor connector went bad (hardwiring fixed those) . it usually has yellow wires and should be a short (0 ohms) if good, open (infinite ohms) if bad