TM10-3930-660-20 8-51. HYDRAULIC BYPASS SWITCH - REPLACE/TEST (Cont’d) NOTE Listen for the emergency steer pump during steps 1c. through 1f. The pump makes a high-pitched sound when it is running. c. Place starter switch in the RUN position, but do not start the engine, TM10-3930-660-10. Check that emergency steer pump is running. d. Turn wheels fully to both sides and check that power assistance is  present. Straighten wheels. To hear the emergency steer pump while the engine is running it may be necessary to go under the vehicle during step le. e. Have assistant start engine, TM 10- 3930-660-20. Check that emergency steer pump stops running shortly after engine is started. NOTE Leave starter switch in RUN position during  step  f. f. Place auxiliary fuel shut-off switch in the OFF position, TM10-3930-660-10.  Check  that emergency steer pump starts running after engine stops. g. Place starter switch in the OFF position,  TM10-3930-660-10. h. Place auxiliary fuel shut-off switch in the ON position, TM 10- 3930-660-10. 2. PERFORM VOLTAGE TESTS ON HYDRAULIC BYPASS SWITCH (1). NOTE Leave electrical leads 10 and 91 connected to switch (1) during steps 2a through 2h. a. Attach positive lead of voltmeter to terminal NC of switch (1). b. Attach negative lead of voltmeter to  suitable  ground. c. Place starter switch in RUN position but do not start the engine, TM10-3930-660-10. d. Voltmeter should indicate approximately 24 volts. e. Start engine, TM10-3930-660-10. f. Voltmeter should indicate approximately O volts. g. Stop engine, TM10-3930-660-10. h. Remove voltmeter leads. 8-163