Cold Weather Modulator

1983 Mercury Zephyr GS, 2.3 A, AutomaticSECTION Cold Weather Modulator
  1. Connect a vacuum gauge to vacuum supply side of modulator. Connect an auxiliary vacuum pump to vacuum motor side of modulator. Apply 16 in. Hg of vacuum with auxiliary vacuum pump.
  2. When modulator holds vacuum, it should not leak down to less than 5 in. Hg. If is does, replace modulator. If modulator temperature is above leak down temperature and it holds vacuum, replace modulator.
COLD WEATHER MODULATOR SPECIFICATIONS

Modulator Color/Type Holds Vacuum @ °F (°C) Leaks Vacuum @ °F (°C)
Brown/Normally Open 5 (-15) 40 (4)
Purple/Normally Open 30 (-1) 60 (16)
Red/Normally Closed 40 (4) 80 (27)
White/Normally Open 40 (4) 80 (27)
RENDER: 1.0x

NO RELATED

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.