If you mean the starter motor/solenoid unit it's located near the bottom of the engine block between the block & the firewall. You access it from beneath the vehicle after removing all of the plastic mud guards.
ignition control module is located under the distributor cap
If you mean the Constant Control Relay Module, it is located under the air filter.
The End Result
In the trunk
Where is the PCM located on a 2005 Mercury Montego Premier?
The cruise control computer module is located on the passenger's side of the engine compartment on a 1993 Mercury Villager.
The cruise control module of a 1993 Mercury Villager is located under the passenger side of the dashboard.
where is the ignition control module located on mercury marquis
Inside the distributor
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The 1999 Mercury Sable computer module can be located behind the passenger side dashboard. The dashboard will need to be removed in order to view the computer module.
That would be inside the polar control unit