MSM Module Does Not Make Relay Click Sound When Any Power Seat Switch Input Is Selected

WARNING: This page is about a different car, the 1998 Chrysler Town & Country. However, it is still accessible from the selected car via links, so may be relevant.

Check power and ground circuits. Using DVOM, check for battery voltage at MSM module 10-pin connector terminal No. 8 (Red wire). Check for continuity between MSM module 10-pin connector terminal No. 7 (Black wire) and ground. Ensure connectors are firmly engaged into MSM module.
To wake up MSM module, shift vehicle into any gear. This provides 3.5-5 volts reference voltage to seat motor potentiometers and mirror position rheostats. Check for sense voltage at MSM module 21-pin and 25-pin connectors. See WIRING DIAGRAMS and appropriate CONNECTOR TERMINAL IDENTIFICATION table below:
Ensure driver's power seat switch connector is seated firmly on switch.
Using DVOM, check for voltage between driver's power seat switch seat switch terminals No. 5 (Red wire) and No. 1 (Black wire). See WIRING DIAGRAMS . If battery voltage does not exist, replace MSM module. If battery voltage exists, go to next step.
Check for driver's power seat switch output voltage at appropriate switch terminals. See DRIVER'S POWER SEAT SWITCH 10-PIN CONNECTOR TERMINAL IDENTIFICATION table. See Fig 1 . If voltage does not exist at all terminals, replace switch. If voltage exists at all terminals, go to next step.

Check for driver's power seat switch output voltage at MSM module 21-pin connector terminals No. 1-4 and 12-15. See MSM MODULE 21-PIN CONNECTOR TERMINAL IDENTIFICATION table under DIAGNOSTIC MODE under SYSTEM TESTS. See Figure . If voltage does not exist at any terminal of MSM module, repair or replace seat wiring harness. If voltage exists at all terminals of MSM module, replace MSM module.

DRIVER'S POWER SEAT SWITCH 10-PIN CONNECTOR TERMINAL IDENTIFICATION

Terminal No.	Wire Color	Description
1	Black	Ground
2	Gray/Light Blue	Recliner B+ Seat Back Front
3	Red/Light Blue	Seat B+ Horizontal Rear
4	Gray/White	Recliner B+ Seat Back Rear
5	Red	Battery Feed To Module
6	Yellow/Light Blue	Seat B+ Horizontal Front
7	Yellow/Light Green	Seat B+ Front Riser Up
8	Yellow/White	Seat B+ Rear Riser Up
9	Red/White	Seat B+ Rear Riser Down
10	Red/Light Green	Seat B+ Front Riser Down

Fig 1: Identifying Power Seat Motor Switch Connector Terminals

Courtesy of CHRYSLER CORP.