E180

Notes on Fault Tree
The third gear switch is a normally closed switch located in the transmission which opens when 3rd gear oil is present. The ECM provides 5 volts on CKT 108 which is grounded when the switch is closed (3rd gear not present). ECM input EI80 will show "LO" when the transmission is not in 3rd gear (CKT 108 grounded) and "HI" when the 3rd gear switch is open (transmission in 3rd gear).
When the transmission reaches 3rd gear the °C status light should appear on the ECC head. If this status light is on when the transmission is not in 3rd gear, CKT 108 is open and must be repaired.

Notes on Intermittents
Manipulate affected wiring while observing the °C status light. If the fault is induced, the °C status light will flash on. Repair intermittent open in CKT 108.