Intellitronix Fuel Gauge Reverse

Installed an Intellitronix setup in my '73 Dart and all of the gauges work well except the fuel gauge seems to be reading in reverse (it counts up as I use gas). The fuel gauge worked well with the old cluster (only gauge that did).

Before I try replacing the sender anyone have any ideas? I made sure the sender was grounded well, and even ran a fresh wire from the sender to the cluster.

Open to suggestions.