Cabin ventilation control should read out "FULL AUTO" when temp control and fan control are both in "auto" mode. Placing fan control in "auto" no longer places unit in "FULL AUTO" and fan control (speeds) have become inconsistent. My first fix attempt was replacement of the resister pack (per previous posts) and manual fan control has improved, but the fan switch in "auto" still fails to place the unit in "FULL AUTO." An entirely new ventilation control unit runs ~$375.00. Are there any known component failures that could cause this malfunction in the fan switch that I could replace/repair other than changing out the entire ventilation control unit?