Code .7.5 Cruise Control on/Off Circuit

Fig. 31 Reverse switch wiring circuit:

The cruise control instrument panel switch sends a 12 volt signal to the ECM when the switch is in the On position. When the switch is turned off, voltage at ECM pin E drops to zero volts. Trouble code .7.5 indicates that the ECM is not receiving the 12 volt signal from the cruise control instrument panel switch when cruise is available. To diagnose the system, proceed as follows:
1. Turn ignition On and cruise On/Off switch Off. Connect one lead of suitable voltmeter to ground and connect other lead to orange ECM connector pin J. If reading of 12 volts is obtained, disconnect orange ECM connector and measure voltage at pin E or J again. If voltage remains at 12 volts, check for short circuit in power feed circuit 903 (397, 1985 models). If wiring is satisfactory, replace cruise control instrument panel switch. If voltage at pin J is zero volts, measure voltage at ECM connector pin A. If 12 volts is available at pin A, repair short to voltage in circuit 402. If voltage at pin A is zero, ECM or ECM connector is at fault.
2. If reading of zero volts is obtained at pin E or J prior to disconnecting orange ECM connector, turn on instrument panel cruise control switch and measure voltage at pin E or J. If reading is now 12 volts, ECM or ECM connector is at fault.
3. If ECM is operating satisfactorily, measure voltage at pin C of cruise control instrument panel switch. If reading is zero volts, check for open or short in ground wire of circuit 350 and repair as necessary.
4. If voltage at pin C of cruise control instrument panel switch is 12 volts, check circuit 903 (1985, 397) for open or shorted ground circuit and repair as necessary. If circuit 903 (1985, 397) is satisfactory, replace cruise control instrument panel switch.