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78 Mark Door Ajar Light, Power Door Lock Issues

Hi Bill,

Once again I could use some advice on my Lincoln. You've helped me in the past and I trust your opinion.

The Door Ajar light is stuck on and the driver's side door doesn't lock either with the key or the power lock control. The power lock control does however work on the passenger side. I'm curious if the problems are related and if you think I have a bad switch on that side or the power lock component doesn't work for the driver's side. Also is this a part I should by new or used if that is the case.



Hi Justin -

To answer your Shop Manual question first, yes we can arrange to send to your address a set of 1978 manuals hot off the press. Another benefit of the manuals is that if you ever sell your car and the manuals are included in the sale, they become a selling feature to the buyer. George will e-mail you with the details.

As for your power door lock problem, your description sounds like the Door Lock Actuator has gone south and is now seized. If so the key will not operate the lock and the door lock switch will only operate the right side as you describe. The Door Open warning switch is also located within this lock assembly as well and it can be inspected for damage at the same time that the actuator is replaced. The above conjecture is based on our experience. The good news Justin is that we have new Actuators available whenever you have finally diagnosed your problem. Let us know the results and feel free to contact us for further information.

Wishing you Good Luck,

Bill and the Lincoln Land Staff