Came out to call for a system not cooling and the thermostat was blank. Customer stated that he put new batteries in the thermostat and the thermostat was no longer blank but the system still wasn’t working. Customer was concerned that we may have done something since we were out to do the maintenance a week or so ago. I checked system over and found unit to have proper power but the door switch to be faulty and the wires were burned. Asked customer about any possible power surges since we’ve been out and they said they might have had one. I told customer I could replace the switch, and just bypass it for now. Customer had me bypass the switch. I’ll look into getting a replacement in the mean time and schedule a time to come back out.