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Modulator Variable-Speed Retrofit Packages

Fan Drive Retrofit

Modulator Retrofit Package

Variable-Speed Retrofit Packages

Prevents Under- and Overcooling in All Climates

From Alaska’s North Slope to the Gulf Coast and any climate in between, you’ll get better engine and cab temperature control by replacing your on/off fan clutch with a Modulator Variable-Speed Retrofit Package. Modulator and your truck’s engine control module (ECM) work together to manage fan speed on heavy-duty line-haul and severe-duty vocational trucks, where on/off fan clutches over-cycle or do not provide optimum performance.

  • Prevents under- and overcooling in all climates
  • Faster cab warm-up, more efficient air-conditioning and quiet, modulated fan speed for improved operator comfort
  • Maximizes engine power to the vehicle drive wheels
  • Improved fuel savings in most applications
  • Long service life under severe duty and reduced downtime


Two Modulator retrofit packages are available. Visit the links below for application and part numbers information.