How check temperature sensor

Hi,

Since yesterday my temperature sensor is giving strange readings… For example here it is summer, the bed at rest is about 27 degrees and the hotend at rest is at 13 degrees…

According to the characteristics of the temperature sensor, it is a Semitec 104GT-2 ATC. With a multimeter I can see what resistance it is giving… But I don’t know what resistance it should give at 25 degrees… I’ve googled and found nothing… Anyone know the resistance they have to give? Is there a table or similar?

Thank you

100BT-5_to_ZS1047U.pdf (785.0 KB)