Rick's Free Auto Repair Advice

Trunk won’t lock Ford

Fix a Ford trunk won’t lock condition

Ford has issued a service bulletin #10-5-9 to address an issue where Ford trunk won’t lock on the vehicles listed below. In these cases, you can slam the trunk but the trunk won’t lock.

The bulletin applies to these Ford vehicles where the trunk latch solenoid is stuck open and Ford trunk won’t lock.

2006-10 Crown Victoria, Focus, Fusion, Mustang, Taurus

2006 Lincoln Zephyr

2007-10 Lincoln MKZ

2010 Lincoln MKS

2006-09 Mercury Sable

2006-10 Mercury Grand Marquis, Milan


Ford states that the problem is caused by an inoperative trunk lid latch solenoid. To confirm this is the problem, Ford recommends the following test procedure:

trunk won't lock

New trunk latch and lock


1: With the trunk lid open, turn the key to the ACC position. Then cycle the trunk lid release button in the passenger cabin. After hearing the latch operate, try closing the trunk lid. If the trunk lid closes and locks, this bulletin doesn’t apply. If it doesn’t close and lock, proceed.


trunk won't lock

New trunk latch

2) Check to make sure the electrical connector is securely fastened to the latch assembly and that the emergency T-handle release is routed correctly.


3) If everything appears normal, replace the latch


8G1Z-5443200-A       Lock assembly for MKS, Taurus, Sable

6E5Z-5443200-D        Lock assembly for 2006-07 Fusion, Milan, Zephyr, MKZ built up to 9/2006

7E5Z-5443200-B        Lock assembly for 2006-2009 Fusion, Milan, Zephyr, MKZ built up to 2/2009

AE5Z-5443200-A       Lock assembly for 2010 Fusion, Milan, MKZ

6R3Z-6343200-B        Lock assembly for 2006-07 Mustang

8R3Z-5443200-A       Lock assembly for 2008-10 Mustang

7W7Z-5443200-A      Lock assembly for Crown Victoria, Gran Marquis

AS4Z-5443200-A       Lock assembly for Focus

The bulletin lists a labor time of .4 hrs for replacing the lock assembly


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Posted on by Rick Muscoplat

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