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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 existing 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 your fan clutch over-cycles or your multispeed fan clutch is not reliable.

  • 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.