Help with Twingo

Hello my name is Juan and I am new in the forum, I have a problem with my Twingo, I still turn on the temperature witness but the engine is cold, I would like to know what tests I can do to identify the problem, probe disconnecting the card and mark the same, I probate bridging the tab and marks the same thing I would like to know how these bulbs would be good to know it good, I appreciate any help.

The temperature vulvo is of the thermistor type when reaching a certain temperature (90 degrees approx) the Checalo circuit is opened or closed with a multimeter and a lighter you have to remove the vulvo, be careful not to burn
when the temperature indicator is turned on

Ok thanks I will try it I have to buy a tester and learn to use it and with that I can try it.

Forgive which multimeter is like a tester?