The manual for my 1430 shows a 20amp. circuit breaker inline with the cooling fan. This circuit comes directly from the battery connection to the starter so it doesn't go through the ignition switch (i.e., the fan can run when the tractor is not running). After the circuit breaker, there is a thermal switch in series with the fan motor. This switch senses the temperature of the hydraulic fluid running through the line to the cooler. My fan doesn't run all of the time, but it does continue to run after the tractor has shut down. It usually runs on hot days when I have been grinding stumps for a few hours. If my memory serves me correctly, I believe that the temperature gauge on the operator's panel, senses engine oil temperature and feeds through the connector on the Duetz engine.
To trouble shoot, I would recommend the following:
1. Make sure that the fan blade turns freely.
2. Check the voltage on the ouput of the circuit breaker. If 12V is not present, the circuit breaker could have tripped or failed.
3. If there is voltage on the output of the circuit breaker, check to see if there is voltage on the input to the thermal switch and make sure the connections are tight.
4. Apply a jumper wire across the thermal switch and see if the motor turns.
5. If not, check for 12V at the motor. If 12V is present, the motor is either not connected or is bad.
6. Chances are that one of the slip-on connectors has come loose. Be sure to also check the ground connections.
7. All of the connections come out of a terminal box which is located on the left rear, inside of the enginer compartment. One of the screws on these terminals could have also come loose.
I hope this helps.
