If you've already replaced the heating element, you need to check the Thermal Cut-Out (TCO). The TCO works in conjunction with the Hi-Limit Thermostat to regulate and protect the heating element. Both of these components are mounted on the outside of the heater box. The TCO is located at the end opposite the heating element terminals, while the Hi-Limit Thermostat is located adjacent to the heating element terminals.
The following link explains how to troubleshoot these components and what the resistance readings should be:
If the TCO is found to be defective, it is recommended you replace the Hi-Limit Thermostat as well. Failure to do so can result in premature failure of any parts you replace. These two components are commonly sold as a set.
Replacement parts (if required) can be purchased at any of the following websites:
All these sites are reputable and offer great service with competitive pricing, so shop and compare. The first three sites I listed also include helpful exploded view parts diagrams to assist you in locating and properly identifying the parts you need. If you do not wish to order parts on line, you can use the part numbers from the Sears website and go to your nearest appliance parts retailer. These components are commonly sold as part of their in-store inventory.
If you have any questions about this repair, please post back and let me know. I hope you find this information helpful.
NOTE: Make sure you verify the power at the wall receptacle before you begin. If you are missing half your input voltage (due to a tripped breaker or bad power cord), the dryer may still run, but won't heat.