Please give me some basic guidance on diagnosing home AC system. The display on the electronic thermostat went dark, but the batteries aren't dead. The on/off switch on the thermostat can still start the air handler in the attic, but the outside compressor won't run. The breaker did not trip off. There was a lightning storm. What can I do before calling the repairman? Thanks. -B
- posted
18 years ago