11 yr old Goodman air handler had a mouse in the blower wheel causing bad vibration. Pulled blower to remove mouse and put back together. Customer was using supplemental propane heat and expressed having headaches using it. I checked for carbon monoxide but didn’t find any readings of it. Recommended carbon monoxide detector in the home. They have elected to get one themselves rather than use provide one for them. Customer was also concerned about a burning smell. Smell was coming from dust burning off the electric strips and smell will dissipate.