Alieware M7700 fans Issues

Hello,

I have an old alienware D9T/M7700 with default specs and 2G of RAM. I am trying to get it back from the grave as it stopped working 3-4 years ago because of overheating. I have noticed that the 2 CPU fans are not turning on when powering the machine. The fans are cleaned and turns on only when the machine overheats and poweroff.

How do I get the fans to turn on when powering the machine? Is there a switch in the BIOS, an upgrade to be made, or computer part to change?

I really love that machine even if it is a fossil.

Thank you in advance for your valuable info on that matter,
INF1