Door not unlocking

91_SC_BIRD

Registered User
For no reason, the door just doesn't unlock anymore, with either the alarm system keyfob or the actual electric lock buttons inside the door, the only way is the key, or the keyless entry. It locks fine, (with the alarm too). I would like to know where should I start looking!

Thanks,
 
If your keyless entry buttons still cause it to electrically unlock, then that rules out the lock actuator. Your keyless keyfob probably uses the same ground that the switch on the door provides. I would look there or somewhere near there for the problem.
 
7birdslater said:
If your keyless entry buttons still cause it to electrically unlock, then that rules out the lock actuator. Your keyless keyfob probably uses the same ground that the switch on the door provides. I would look there or somewhere near there for the problem.

The thing is that the buttons on the driver and passenger side don't work (to unlock) yet with the keyless entry, everything works fine. it has to be a common connection somewhere. Just not too sure where I should be looking :confused:
 
If you can get your hands on a Ford EVTM (electrical and vacuum troubleshooting manual), that is a great resource. It shows detailed diagrams of each electrical system. I used to have one, but I gave it to my uncle when I gave him my old 1989 base Thunderbird. Maybe someone on this site could scan the relevant pages for you.
 
You need to check the wire that's marked in red. There probably is an open somewhere along it, most likely where the after-market alarm connects to it.

Splice S430 (blue arrow) is below the rear of the driver's side door sill.

Another possibility is that the Keyless Entry Module's #11 pin doesn't work. You can check it using a short length of wire. Connect one end to a ground point and touch pin #11 with the other end of the wire. If it's working, the doors will unlock. You can also perform this test at splice S430 to check the wire marked in red.

The alarm may tap into the wires that run from each door switch to splice S430. I doubt this is the case as both sides have stopped working at the same time.
 

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