5 cycle dryer. sometimes it heats sometimes it doesn't

try here...
https://www.repairclinic.com/RepairHelp/How-To-Fix-A-Dryer/8-200-684343-/new/LG-Dryer-not-heating-DLG3744W
they also have a chat and 800# to ask questions if your'e not sure.
hope this helps.

Hi cayjr1

Clogged Vent
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.
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 the heating element. You can check for an ohm reading but will need to refer to the service manual for proper reading. This sometimes on the tech sheet located somewhere on the dryer. Usually between 9-13 ohms.
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 . This thermostat usually has four wires going to it. Check the 2 terminals that are opposite each other and are the closer together of the 2. These 2 terminals should have continuity. If not replace the thermostat.
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Bud

My whirlpool dryer Model GGW9896KQ2 seems to run ok but it doesn't seem to heat up properly and takes several cycles to dry clothes. I checked the exhaust vent and it seems to be blowing air out ok. Also, it appears the dryer goes to the cool down cycle way to early. In addition, the dryer will sometimes shut off before the time is acutally done. help--I don't want to spend money for a tech or even a new dryer. It's only 8 years old.

Hi, If you have a gas dryer.
The most common problem with a gas and no heat is the ignitor going bad...

Here is a tip that I wrote about that problem...

Gas Dryer not Working Gas Dryer Not Heating
http://www.fixya.com/support/r4398592-gas_dryer_not_working_gas_dryer_not

If your dryer is electric..
There could be a number of different problems...
Check out this tip that I wrote about this problem...

Dryer Troubleshooting Electric Dryer won t Heat
http://www.fixya.com/support/r3866345-dryer_troubleshooting_electric_dryer_won

heatman101

sounds like you have a connector that is loose.unplug dryer and check all wire connectors.

try timed dry cycle instead of the auto-sensing setting. In your drum if you have auto dry such as less dry normal dry and more dry, There is a sensor sometimes in the drum and sometimes in the exhaust right after the blower. If in the drum then your clothes brush by this and if moisture is sensed then it keeps on drying. With your rack the clothes can't touch the sensor so it tells your dial to turn and that items are dry which in fact are not. Try this and see how it does.

this is joyce
It is as you guessed your sensor. it is usually located in door but some models are in back of machine on inside, go online download document papers go to maytag.com put in model# and then download your model # and it will show you where your sensor is located, it should be simple to replace. I had the same problem with my dryer.
I am glad you said you checked the dryer lines because if these get clogged up they will cause the dryer not to dry the clothes correctley. very smart....if you need me to help let me know.

thanks,

joyce

1. unplug your machine and rach as far in the exhaust part of the dryer to see if there is an obstrucxtion. 
2.Take out the lint filter and make sure there are no gaping holes in the screen
3. Check the exhaust house leaving the machine or blockage, this hose should not run more than ten feet for optimal drying time.
4. its your heating element

I'd check for a clog in your vent line. I had the same problem before.

Are you running the dryer in a relatively humid environment?