Check the radiator temp. Are there any cool spots? If so the radiator may be partially plugged up.
Is there a lot of debris preventing proper air flow through the condensor and radiator?
If the engine is hot and you can stop the fan clutch with your hand, its not working. Also even if the fan clutch is not working the engine temp should come down when the vehicle starts moving.
The low speed fans should not cycle all the time. They should run with the A/C on and should cycle with A/C pressure.
92 Volvo 740 Wagon aka "Mutt mover"