Dryer runs well but will not heat up and dry

Sure the outside vent is not clogged up? If so it will overheat and turn it self off and do a poor job of drying the clothes.

Also check and make sure that all of the heating elements are working properly.

If your dryer seems to run forever, it could be because of a clogged vent or internal ductwork. Your dryer may have an automatic cycle that turns off the dryer when the clothes are dry. It does this with a special thermostat or moisture-sensing system.Normally, this is what happens during an automatic cycle: The thermostat tells the dryer to heat until the interior of the dryer reaches a pre-set temperature--say 135 degrees. When the dryer reaches the pre-set temperature, the thermostat tells the timer to begin advancing. (If there's a moisture sensor, the timer advances only if the moisture content of the clothing is low enough.) The timer advances until the interior cools, then the thermostat tells the timer to stop advancing, and tells the dryer to start heating again. This cycle continues until the clothes are dry. But...if the vent is clogged, the dryer may never reach the proper operating temperature, so it doesn't send the signal to the timer and the dryer continues to run indefinitely, even if the clothes are completely dry. To fix the problem, clean the vent and/or internal ductwork.

make sure the vent system is clean. any restrictions can cause the safety switches to activate and turn off heaters. When it cools, the switch resets and starts heating. Unit will continue to cycle the heat off and on. Make sure all elements are working.
Start there.

clean out the exhaust vent tubes thoroughly. the moister sensor will shut down the high heat if clogged full of lint

You have checked a lot already ... thanks for the comlete story. Often the questions here hurt for detail.

Are your clothes getting hot?

Two reasons for not getting dry ...

No heat

No air.

You need warm air (heat and air) going through your drier to achieve dryness.

Sounds like you have no heat. Are you properly setup on the control panel (you selected heat)? You have physically inspected the entire exhaust sustem including the outside vent, hose and lint trap - absolutely clear ...

check the heat my friend

If your dryer is taking more than an hour, check these. Vent Frequently there's an obstruction in the vent duct from the dryer to the outside of the house. For the dryer to heat properly, the duct must be clean and clear of lint or any other substance. Heating element Your dryer's heating element may be partially burned out. If it is, your dryer still heats, but at such a low temperature that it takes three or four times as long to dry the clothes. If the element is partially burned out, replace it. Internal ductwork Your dryer has some internal ductwork. If it gets clogged, your dryer can't dry properly. In most dryers, to get to the internal ductwork to clear the clog, you have to substantially disassemble the dryer. A quick way to check for internal clogs is to remove the lint filter and use a flashlight to inspect the inside of the duct. If it looks clogged and you can't clear it using your vacuum, contact a qualified appliance repair technician. Cycling thermostat Although this isn't a common problem, one of the thermostats that controls the temperature in your dryer may break and cause the dryer to heat poorly. If so, you need to replace it. The thermostat is usually a small, round, black device mounted to an oblong steel plate. The plate is mounted to the internal ductwork with two screws. It overheats Usually when an electric dryer overheats it's because of a defective cycling thermostat or a clogged vent system. Clean any lint from the internal and external ductwork, and/or replace the cycling thermostat (read about cycling thermostats in "Drying is too slow," above). It seems to run forever If your dryer seems to run forever, it could be because of a clogged vent or internal ductwork. Your dryer may have an automatic cycle that turns off the dryer when the clothes are dry. It does this with a special thermostat or moisture-sensing system. Normally, this is what happens during an automatic cycle: The thermostat tells the dryer to heat until the interior of the dryer reaches a pre-set temperature--say 135 degrees. When the dryer reaches the pre-set temperature, the thermostat tells the timer to begin advancing. (If there's a moisture sensor, the timer advances only if the moisture content of the clothing is low enough.) The timer advances until the interior cools, then the thermostat tells the timer to stop advancing, and tells the dryer to start heating again. This cycle continues until the clothes are dry. But?if the vent is clogged, the dryer may never reach the proper operating temperature, so it doesn't send the signal to the timer and the dryer continues to run indefinitely, even if the clothes are completely dry. To fix the problem, clean the vent and/or internal ductwork

if the clothes are warm after the cycle then you need to make sure the vent to the outside of the house is not plugged if they are not warm then it is in the heating circuit of the dryer wether it be the element or a fuse will have to be tested. to dry clothes it takes heat and air flow if you dont have one of the two they will not dry correctly

If your dryer seems to run forever, it could be because of a clogged vent or internal ductwork. Your dryer may have an automatic cycle that turns off the dryer when the clothes are dry. It does this with a special thermostat or moisture-sensing system.

Normally, this is what happens during an automatic cycle:

• The thermostat tells the dryer to heat until the interior of the dryer reaches a pre-set temperature--say 135 degrees.
  
  
• When the dryer reaches the pre-set temperature, the thermostat tells the timer to begin advancing. (If there's a moisture sensor, the timer advances only if the moisture content of the clothing is low enough.)
  
  
• The timer advances until the interior cools, then the thermostat tells the timer to stop advancing, and tells the dryer to start heating again.
  
  

This cycle continues until the clothes are dry. But…if the vent is clogged, the dryer may never reach the proper operating temperature, so it doesn't send the signal to the timer and the dryer continues to run indefinitely, even if the clothes are completely dry. To fix the problem, clean the vent and/or internal ductwork.

Hi first are you sure your heating element is good and working is the dryer getting hot in side when you open door to check clothes.if they are and you are sure the duct work is clear and no clogs, you might try this I have heard this from other people take your lint filter out and wash good with hot soapy water they say that after so long using dryer sheets this filter can get a invisible coating on it.
Hold the filter under water and see if it will holds water I know it sounds crazy but I have heard it from more than one source.

first take the venting off the back of the dryer and dry a load if dryes normal replace venting if takes a long time to dry have a repair man clean the dryer