Heater fan not working in all positions

Hello, I'm new to this. I have a 1994 Cav. fixing it for my son as a first vehicle. The heater fan does not work, checked the heater fan coil ( has 3 different diameter coil wires) it's OK.

What else do I check for, unfortunatly the car didn't come with a maintenance manual.

I am sure this is not a difficult problem to resolve, just need to know location of relay or fuses.

Thanks,

Romeoted.