the power button of the heat stop working there is no heat inside my 2003 Honda Odyssey
Check the fuses and relays first. If this is a manual heat control the next thing would be to check the blower motor resister and then the blower motor itself. If this is an automatic climate controlled system, the next thing to check would be the blower power transistor. The last thing would be the control head unit. Of course all testing should be done with a fully charged battery. Use the wiring diagram provided to gain a better understanding of how the circuit works.