Switch Test Mode

The switch inputs used by the SMEC have only two recognized states, HI and LO. For this reason, the SMEC cannot recognize the difference between a selected switch position versus an open circuit, a short circuit, or a defective switch. However, if any one of these subject switches is toggled, the controller does have the capability to respond, indicating that it has recognized a state change. If the change is displayed, it can be assumed that the entire switch circuit to the SMEC is functional.

SWITCH TEST
1. Connect tester C-4805 or equivalent and access fault codes.
2. After Code 55 has been displayed, indicating end of fault code display, observe tester display and operate switches as follows:
a. Operate brake lamp switch by depressing and releasing brake pedal.
b. Operate neutral safety switch by moving shift selector through range.
c. Ensure that A/C dampened pressure switch is closed, then cycle A/C compressor clutch on and off with blower switch in on position.
3. As each switch is opened and closed, numerical read-out on tester should change. The Check Engine Lamp will also blink.
4. If read-out does not change as switch is operated, check continuity of wiring between switch and SMEC and repair as needed.
5. If wiring is satisfactory, test each switch individually.