There are 5 things that would not make the dryer heat up i will post you them here ok
It is possible that your dryer isn't heating because its heating
element is defective. Heating elements are irrepairable. If yours has
ceased to function properly, you will have to replace it. Open your
dryer's cabinet and locate the heating element so that you can test it.
Another possible cause for a dryer not heating up could be attributed
to a faulty thermal fuse. Once a dryer's thermal fuse has blown, it is
no longer of any use. If your dryer's fuse is blown, you will have to
replace it. Open up your dryer's cabinet and locate its thermal fuse so
that you can test it.
If any of your dryer's thermostats have become defective, they could be
the reason that your dryer is not heating. Open up your dryer's cabinet
and test each of your dryer's thermostats. If any are faulty, replace
A defective timer motor could also cause your dryer to not heat up.
Test your dryer's timer motor. If it is no longer functioning as it
should, replace either the entire motor assembly, or just its motor.