I have a roper RES7646KQ2 and it will dry in the
clean out the vent line and the dryer,unplug it,remove the two screws in front of the lint filter on top,then remove the vent line,remove the back panel,on the left side you'll see the metal duct that the lint filter slides down into,take out the four screws that hold it in if you didn't take out the two screws on top do it that holds the filter duct in from the top.clean the duct out,you should do this once a year if it's gas and once every 18 months if it's electric,put it back together and see how it runs,if you have a long vent line you can stick a leaf blower into the vent line and blow it out to the outside,after you have the dryer running go outside and make sure it's blowing air outside and the flapper is opening,if it still doesn't run in auto you could have a bad timer but clean it out first and go from there.if it's blocked with lint the dryer heat won't stay on long so the timer might not advance in the auto cycle,on timed dry it counts down like a clock but on auto the heat comes on,when it reaches temp. the heat shuts down and then the timer starts to advance a little at a time then when it calls for heat the heat comes on and the timer stops advancing,it will do this until the clothes are dry so if it's blocked the heat doesn't stay on long enough to reach temp. to advance the timer.