LG dryer won't stay running.

[griffyar]

My LG dryer starts than stops after a few seconds. I don’t know if the heat is working because it doesn’t run long enough to check. The drum turns freely and I have cleaned all traces of lint from the vent, cabinet, etc. It has not dried very well for quite some time now. I replaced a couple of drum rollers and the drive belt a little while ago, but it kept working after that until now. I’d appreciate any troubleshooting tips as I don’t know what sensors to check, if any, or if I should be looking at the drive motor or heating element. Thanks