Why is my laptop not getting power to the cooler?

Question

Electronics

Laptop Sony pcg-6h4l.
The cooler itself is good, I checked it. I measured the output power for it with a multimeter, it was 0.9v, then it completely disappeared.
I won't take it to the service. How can I diagnose and find out which node is out of order?

Answer 1

Look for a diagram, the laptop is old, it should be. And look at the cooler power supply harness.