John, Check and make sure the duct under the lint filter and the blower housing and wheel are not blocked with lint or obstructions. Check the vent hood to make sure it's not blocked or damaged, etc. The thermal fuse is rated at 200 dgrs.F. and will "open" if there is an air flow problem. It's not "mandatory" to replace the thermistor when the thermal fuse fails, but it's a real good idea if you do. Of course, recheck the basics, lint filter clean, overloaded, etc.

John, check and make sure the heater element and wiring aren't shorted to ground, and/or the gas valve isn't "sticking" open. Then replace the thermistor, as a possible issue. A proper model number would be helpful. Thanks,

John, That's a tad bit high, should be 10K ohms at room temperature(77 dgrs.F.)see the attached tech sheet for testing and accessing the components needing to be checked.

John, Depending on the meter, if you have a 10k setting(or in your case a 20k setting) the 1k or rx1 setting is too low to read the proper resistance and you won't register a reading. On the higher settings 100k or 200k, you slide the decimal point over one digit.
We would expect to see 10-11K ohms resistance on the thermistor at room temp, but (70-77° F.) = 11.5–13.5 k ohms. is the recommended resistance range. A tad bit high, but within the resistance range, and should not affect the heat operation of the dryer, or cause the thermal fuse to open. But you may want to change it anyway.