Astro, Safari, C, G, K, S & T Series
Digital Ratio Adapter Controller (DRAC) is a solid-state device used to change AC voltage signal from the VSS to a digital signal for speedometer operation.
The DRAC is matched to the final drive ratio of each vehicle. If the final drive ratio is changed for any reason (i.e. tires or gears), to maintain accurate speedometer/odometer reading the DRAC must be replaced on Astro/Safari, G, S and T Series, or recalibrated on C and K Series.
NOTE:
Incorrect DRAC calibration will affect Rear Wheel Anti-Lock Brakes (RWAL), Electronic Control Module (ECM), and Cruise Control Module (CCM).