Test B: No Communication With Rear Electronic Module

NOTE: Turn ignition switch from LOCK to RUN position to enable system power feature.

Turn ignition switch to LOCK position. Disconnect Rear Electronic Module (REM) harness connectors C342(26-pin), C343 (20-pin) and C344 (12-pin). See Figure . Turn ignition switch to RUN position. Measure voltage between ground and REM harness connector C343 terminal No. 3 (Light Green/Red wire). Measure voltage between ground and REM harness connector C342 terminal No. 13 (Tan/Red wire). Measure voltage between ground and REM harness connector C344 terminal No. 4 (Tan/Red wire). See Figure , Figure and Figure . If all voltages are 10 volts or more, go to next step. If any voltage is less than 10 volts, repair open in power supply circuit(s). See POWER DISTRIBUTION article in WIRING DIAGRAMS.
Turn ignition switch to LOCK position. Disconnect REM harness connector C341(22-pin). Measure resistance between ground and REM harness connector C342 terminals No. 11, 25 and 26 (all Black wires). Measure resistance between ground and REM harness connector C341 terminal No. 12 (Black wire). See Figure . If all resistances are less than 5 ohms, repair module communications. See MODULE COMMUNICATIONS NETWORK - WINDSTAR article. If any resistance is 5 ohms or more, repair open in Black wire(s).