It could be the blower motor resistor

I have a 02 Grand Prix GT. The only way the fan, headlights, dash lights, and info centre work is if I turn the car on with the fan setting on 5. I cannot turn it down or it will shut the system off and will not turn back on again unless I restart the car. At one point the whole system wouldn't turn on at all, so I took it to the mechanic and they replaced the daytime running light sensor, which worked for about a week. Now it only works as previously stated, on 5 speed. I have also had the blower motor replace prior to this sensor being replaced as it was burned out. I have read on the internet that it could be the blower motor resistor, could this be the actual problem? Thanks!