I arrived at a customer's home to perform a routine maintenance check on their heating and cooling system. Upon arrival, I noticed that the thermostat had an error code indicating a communication issue. I proceeded to check the power control board, which was shorted out, preventing it from receiving any communication signals. I informed the customer of the issue and explained that a service package was not necessary at this time. I provided them with some troubleshooting tips to try before scheduling a service call.