Dryer Repair

My dryer is working but the clothes are not getting dried probably it is not blowing hot air and I need to know how do I check which part need to be replaced.
Whirlpool Heavy Duty Thin Twin Mod LTE 5243DQ3 Serial MP2565712

If the dryer heating (it is warm inside during the cycle) but not drying, then the problem is a clogged vent line. It has to be professionally cleaned all the way from the dryer through the vent outlet.

Gene.