blower fan blows when not using airconditioning.no air comes out of vents

The blower is located under the hood. I replaced relay ,it did not fix it

Ok, if the relay is not an issue, that means it is receiving the signal to turn on the blower motor. Remove the A/C control unit, and with the vehicle off, blower motor running (i.e. when it is acting up), check for voltage entering the control unit. There should not be any voltage at all, and all controls should cease to function. Also, unplug the control unit to see if the fan stops. Let me know what you find.