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Registered
1977 Eldorado, 1973 Sedan DeVille
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52 Posts
Discussion Starter #1
All the power locks on my 4 door sedan DeVille do not work. When attempting to open or close them they buzz a little but nothing happens. I removed the rear left door lock actuator and tested it with my PowerProbe and it works fantastically! Really strong, both ways. I am now thinking on a common fault and was wondering if there is a relay for the door locks and if so where it would be?

Appreciate your assistance.
 

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77 CDV, 06 DTS III, 69 FWB
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10,022 Posts
No relay. but there is a fuse. Your owner's manual or shop manual will show you which one. If the fuse is good, and neither door lock switch makes the locks work, time to start tracing circuits.
 

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Registered
1977 Eldorado, 1973 Sedan DeVille
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52 Posts
Discussion Starter #3
Not the fuse. I guess I will have to start taking the door lock actuators one by one and hopefully find the offending one. Hopefully is not a wiring problem....

Here's a pic of this beauty!

IMG_1262.JPG
 

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1979 Coupe deVille, 1995 Sedan DeVille (sold)
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1,846 Posts
How easily do the locks move when you operate them manually?
If they're stiff, you may need to clean and lubricate them. Perhaps the power locks work, but just can't overcome the resistance.
Have you disconnected the actuator from the lock mechanism and tested it installed in the car?
 

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1977 Eldorado, 1973 Sedan DeVille
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52 Posts
Discussion Starter #6
Have you disconnected the actuator from the lock mechanism and tested it installed in the car?
They are a bit stiff but not so much as to prevent the lock from working. However, your suggestion for disconnecting the actuator from the lock mechanism and testing it is *perfect*. I shall try this and report back.
 

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1977 Eldorado, 1973 Sedan DeVille
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52 Posts
Discussion Starter #7
So after doing some electrical testing, I realized that when the lock or unlock button was pressed both prongs going to the rear left door lock actuator lit up to 12 volts. This did not make sense. When you hit lock, one would light up and when you hit unlock the other lights up. The case for the actuator is the ground. I tested the left rear actuator outside the door with my power probe and it was perfect. So, I knew there was a short somewhere. My second door was the drivers door. I took the actuator out (there was only one bolt holding it to the door) and tested it and there it was. It did not work. After removing it and hitting the lock/unlock switch, the remaining two actuators workeed! (they struggled but worked).

IMG_1338.JPG

I opened the actuator up and here it was: The wire was stripped of its insulation and touching the case. Evidently since the actuator was held by only one bolt, the vibration most likely cause the insulation to rub on the case and take it off. I repaired the exposed wire with electrical tape and silicon, put it back together and presto! It worked like a charm

IMG_1341.JPG
 

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1980 Eldorado, 1974 Talisman, 2004 Volvo C70, 1975 Fleetwood 'd Elegance
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7,958 Posts
You rock man!
Great job and thanks for the follow-up.
 
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