Code .7.3 Drive ADL Switch Circuit

Fig. 29 Drive switch wiring circuit:

Fig. 30 Drive switch wiring circuit. 1985:

When transmission is operating in drive, the ADL switch is closed and supplies a 12 volt signal to the ECM. Code .7.3 indicates this signal is not being received by the ECM. To diagnose the system, proceed as follows:
1. Check condition of 20 amp body fuse. If fuse is blown, replace fuse, repair short in circuit 340 or 243 and perform switch tests. If fuse is not blown, proceed to step 2.
2. Ensure drive switch opens as shift linkage is moved from drive to neutral, and adjust as necessary.
3. Turn ignition on and display Code .7.3. Disconnect drive switch electrical connector, then connect and disconnect a jumper wire across connector pins.
4. If Code .7.3 passes after jumper is removed, replace drive switch. If Code .7.3 is still displayed after jumper is removed, proceed to step 5.
5. Check circuit 243 for an open and repair as necessary. If circuit is satisfactory, measure voltage on circuit 340. If 12 volts is not measured, ECM or ECM connector is at fault. Repair or replace as necessary.