New owner, ac fan runs when called for but turns off on auto. Tried two different thermostats.

While the fan for the ac works when set to fan, the ac fan in the attic turns on and will stay on. However, the thermostat is set to auto, the fan turns off and nothing happens. Fan stays on for heat and functions in auto. I'm at a loss.

The original thermostat looks like it is a Honeywell t 87

We put in a Nest thermostat (3rd gen) as right after buying the house and the same issue is happening. So I don't think it is the thermostat itself...

Any help here?

The wires are Y, G, W, R

submitted by /u/swamprat3
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