I posted this (or thought I had) before, but the site says I have never posted a question so please excuse the repost if the original does show up.

I have a Carrier system that exhibited erratic heating over the winter.
The air handler would act like it was working properly because it's blower would turn on or off based on the thermostat setting. But the air was generally not warm. Occasionally it would put out hot air without much force and I assumed it was getting heat from the strips.
I discovered that the compressor/condenser fan was rarely coming on. When it did, if I checked the air registers you could definitely tell it was blowing hot air.
I am not sure where to start to look. I feel it has something to do with the outside portion of the system, but I could be off mark. Any help would be appreciated.