I'm so frustrated with my Crossfire
All of this started after my battery died and my alternator failed. Both of those were replaced.

Thought the fan failed as it will overheat if stuck in traffic, and as suggested here, if it doesn't run while idling with the AC on, it's probably failed. I swapped out the cooling fan with a new one last weekend (at least they engineered it to be easily swapped), but when I tested it by turning on the AC and letting it idle, the fan never came on.

The coolant reservoir warning light on the dashboard is on, so I was thinking I should replace the coolant tank/sensor next as that's what it's complaining about. Would a failed coolant tank sensor keep the fan from running?

My next step if the coolant tank sensor doesn't resolve the issue is the fan control box.