Cold Weather Modulator
- Connect a vacuum gauge to vacuum supply side of modulator. Connect an auxiliary vacuum pump to vacuum motor side of modulator. Apply 17 in. Hg of vacuum with auxiliary vacuum pump.
- When modulator is activated, 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 holds vacuum, replace modulator.
COLD WEATHER MODULATOR SPECIFICATIONS
| Modulator Color/Type | Holds Vacuum @ °F (°C) | Leaks Vacuum @ °F (°C) |
|---|---|---|
| Brown/Normally Open | 15 (-9.4) | 30 (-1) |
| Purple/Normally Open | 40 (4) | 55 (13) |
| Red/Normally Closed | 50 (10) | 60 (18) |
| White/Normally Open | 50 (10) | 76 (24) |