a) Create a vacuum of 285 mm Hg on the switch. (or more).
b) Measure the resistance between terminal "1" and the switch housing.
- Resistance: about 0.7 ohm at 20°C
If the resistance is not as specified, replace the fuel heater assembly with the vacuum switch.
2. Checking the conductivity of the switch.
Using an ohmmeter, check for continuity between terminal "1" and the switch housing.
If there is conductivity, replace the fuel heater assembly with the vacuum switch.
3. Checking the operation of the switch.
a) Create a vacuum of 285 mm Hg on the switch. (or more).
b) Using an ohmmeter, check the conductivity between terminal "1" and the switch housing. If there is no conductivity, replace the fuel heater assembly with the vacuum switch.