Elec dryer, low heat, moisture monitor reads low moisture

Dryer now takes 1 1/2 hrs to dry even a small load. I was in the dryer a few months back to replace bushings & belts. I thoroughly cleaned the insides & the vent is blowing out fine. This started a couple of days ago. Like I said low heat only, so it takes 2 cycles to dry. Timer cycles fine and shuts itself off but the moisture monitor only sees low moisture so maybe the monitor circuit is not letting the heater go full blast on wet clothes.

Is this a moisture monitor problem or a heating element problem?