2005 hyundai tucson v6 passenger side heated seat will not warm up the light comes on. driver side is ok could it be the switch even if the light comes on

Possibly.... the only way I know to diagnosis this issue is with an amp meter in the circuit that heats the seats. Compare LH & RH seat heating current draw. If you find the pass seat is NOT drawing the same amount of current, further troublshooting is required. There are TWO heating elements installed in the seats -- seat bottom & seat back, and they are connected in 'SERIES'... so if either element goes/is 'OPEN', then it's component replacement time. There is a thermostat in the heating elements -- it regulates the seat temperature. One must isolate the two elements & check each one individually (seat bottom - checking resistance... and seat back - checking resistance). whichever one (or possibly both) are 'OPEN'. If you find resistance is normal (3 to 5 ohms), then the problem/cause may be in the switch (or its contacts). Using a test light (12 volt bulb), check for power (battery voltage) at the heating element connector to ground (chassis). If the bulb lights up, you know you have power at the switch and is sending it to the heating elements.