2010 Avenger. Started out only happening when 1st started. Now it does it once in a while during driving. Is there a relay behind the glove box?

 

Most likely the HVAC blend doors moving around. Or, one of the actuators is stripped.

 

Yes iy is in fact behind the glove box and it is the vent actuator or blend door it switches from hot to cold air and is getting stuck . If it is let go it will stop making noise for awhile . But it will eventually cause hit air to blow out the driver side vents and cold air to blow out the passenger vents.