BE-46 BODY ELECTRICAL SYSTEM — Combination Meter 3. MEASURE TURBO METER RESISTANCE (a) Disconnect the two drive circuit wire harnesses from the turbo meter terminals. (b) Measure the resistance between terminals. Resistance: Approx. 72 Ω If resistance value is not as specified, replace the turbo meter. If resistance value is not as specified, replace the turbo meter drive circuit. 4. INSPECT PRESSURE SENSOR (a) Connect a series of three 1.5 V dry cell batteries. (b) Connect the positive (+) lead from the dry cell batteries to terminal 3 and the negative (—) lead to terminal 1. (c) Connect the positive (+) lead from the voltmeter to terminal 2 and the negative (—) lead to terminal 1. (d) Check that the voltage between terminals 2 and 1. Voltage: Approx. 1.5 V (e) Apply 200 mmHg (7.87 in.Hg, 26.7 kPa) of vacuum. Check that the voltage drops below 1.5 V. (f) Using SST, apply 0.5 kg/cm² (7.1 psi, 49 kPa) of pressure. Check that the voltage rises above 1.5 V. SST 09992-00241 If operations are not as specified, replace the sensor.