HOT HOT HOT 86 Porsche 944 Temperature gauge not working and fans stopped working too : ( please Help!

How can I get these fans to start running again? There is supposed to be something that tells them when it is time to turn on and I am not sure where to start.

The backstory. When I bought the car last year the temp gauge worked and I found it running too hot quite often. I noticed that one of the fans wasn't running and found it unplugged. Problem was solved. Then the temp guage decided not to work for a few weeks then it came back and then gone again for months. During this time the fans continued working. When the engine did get too hot from idling while sitting still the red light on the temp gauge would illuminate even without the gauge working. This light still works, the gauge still does not and more importantly the fans have not come on in weeks.

I have been driving it as little as possible and when concerned about overheating I run the heater to reduce some of the heat under the hood.

I don't think it is the fan relay but I suppose that is possible as well.

This car won't last long overheating as often as it is and I would like to order some parts and begin this repair as soon as possible with your advice and kind instructions of course : )