Not heating . heated fine one minute and no heat the next. do not know much about them/

The heating element have got old and brittle over time and finally gave up the ghost. But it is not always the element. It could be one of the safety Hi-limits have blown. All parts of the dryer will have continuity if its working properly. Test for continuity by using a meter set on Ohms,or use a poor man's meter. You can make your own poor man's meter by using an ordinary flashlight . Break the circuit in the flashlight and add a couple of wires to it so that you can make the light come on in the flashlight, that's right hot wire that flashlight. When the bulb lights up you have a circuit! You now have a poor man's meter. The next step is to check each little gizmo on the dryer that the wires attach to. All the limits attached to the side of the heat element, the door switch (when door is closed) etc.should have continuity (closed circuit)(the light should come on in the poor man's meter) If you come across an thing near the blower housing with 2 wires attached to it, that is a thermal limit, a safety or a control thermostat (So as not to get a false circuit you need to remove one of the wires to each thing you check) Look for lint buildup or blocked vent going out the house. If everything is good and you have paid the electric bill, then the timer could be bad.