Electrical Signal

Fig. 12 Vacuum routing:

NOTE: Model is equipped with both leading and trailing vacuum control solenoid valves.
1. To check electrical signal on leading vacuum control solenoid valve, proceed as follows:
a Start engine and allow to reach normal operating temperature. Shut engine off.
b. Connect tachometer to engine, then connect positive lead of voltmeter to "G" terminal of leading vacuum control solenoid valve coupler (brown coupler) and negative lead to ground.
c. On automatic transmission equipped vehicles, place selector lever in "Park" position.
d. Start engine and allow to idle. Observe voltmeter. Voltmeter should read close to zero volts.

NOTE: If selector lever is moved out of "Park" position on automatic transmission equipped vehicles, voltmeter should read approximately 12 volts.
e. Accelerate engine to 2000 RPM, then allow engine speed to decrease to 1000-1200 RPM. Voltmeter should read near zero volts.
f. Disconnect electrical coupler from No. 1 water temperature switch, then connect a jumper wire to terminals in coupler.
g. Pull out choke knob and increase engine speed to 2000 RPM, then disconnect coupler to No. 2 water temperature switch at radiator. Voltmeter should read approximately 12 volts. Push choke knob in.
h. Disconnect jumper wire and reconnect No. 1 water temperature switch coupler, then accelerate engine to 3000 RPM. Allow engine to decelerate and observe voltmeter. Voltmeter should read near zero volts.
2. To check electrical signal on trailing vacuum control solenoid valve, proceed as follows:
a Start engine and allow to reach normal operating temperature. Shut engine off.
b. Connect tachometer to engine, then connect positive lead of volt meter to "GL" terminal of trailing vacuum control solenoid valve coupler (green coupler) and negative lead to ground.
c. On automatic transmission equipped vehicles, place selector lever in "Park" position.
d Start engine and allow to idle. Observe voltmeter. Voltmeter should read close to zero volts.


NOTE: If selector lever is moved out of "Park" position on automatic transmission equipped vehicles, voltmeter should read approximately 12 volts.

e. Gradually accelerate engine to approximately 2500 RPM and observe voltmeter. Voltmeter should read approximately 12 volts. Allow engine to decelerate to idle and observe voltmeter. Voltmeter should read close to zero volts.
f. Disconnect electrical coupler from No. 1 water temperature switch, then connect jumper wire to terminal in coupler.
g. Pull out choke knob and increase engine speed to 2000 RPM, then disconnect coupler to No. 2 water temperature switch at radiator. Voltmeter should read approximately 12 volts. Push choke knob in.
h. Disconnect jumper wire and reconnect coupler to No. 1 water temperature switch.
i. Disconnect electrical connector from No. 2 water temperature switch, then gradually accelerate engine to 1O00-1200 RPM. Voltmeter should read approximately 12 volts.