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1988 Cadillac Deville Power door locks not working.

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Good evening fellow Cadillac Drivers.


Been thinking for a while I should tackle a small problem with the cars power door locks.


They are out cold on all doors except the right passenger door, Mine is a 4-door.

Also noteworthy is that on the driver's side the following is also out:

No light in the red little lamp in driver's side door.

Cigarette lighter is out in the driver's side door.

The big white light with Cadillac emblem is also out, the car has 2 of these.

One on each side of the back window on the inside.

No power running to or through the above faulty items.

The bulb in the red and white lamps are ok and not broken.


This is what I have done so far:


Checked all fuses in fuse panel/block on the inside of car, underneath the left side of the steering wheel.

Checked and tested all the relays in the relay block, I had 2 new that I also swapped between.

But they all do seem to work.

Changed the + and - battery attachments. Full power coming out of a new battery that has just been changed.


What to do next?

Any creative ideas?

What is there I have missed?


Sincerly Klas

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I would check the wire pass-through at the drivers door. With the drivers door open and ignition in "acc" or "run", grab the harness conduit from the body to the door at the bottom and "move" it in all directions while holding one of the non operating window switches. If they work or work only for a second when moving the harness, slide the door pass-thru "conduit" to one side and see if you can see a wire rubbing, if not move it in the other direction and check the wires again. If there is no change remove the door panel on the drivers door and check the wiring harness for chaffing or check the window switch for burnt wiring. If you still can't find any thing obvious you will have to check the circuits with a test light.

One thing to remember, window switches reverse polarity they do NOT switch the ground. 


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No luck so far.


I did try to jerk that whole wireloom that runs into door, did nothing.

Took out the switch for the front door lock.

Measured, and voil'a. no juice to that contact. So somwhere along the cables it does not send any juice. hm.

Works on the right side just fine though.


Also took out the small switch for the door lights, no power.

Inside opera light, and the red lights in the doors. No power.


Tried to look through these wiring diagrams, but can´t seem to find what I am looking for.

Anyone inclined in this with better glasses than me :) ?





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It sounds like you are making progress.  Do you have the wiring diagram?

Look for slices, they corrode sometimes.

If the circuit is fed by a common fuse check fuse for continuitity and for power at the fuse.  Keep following the circuit back.  Do you have the manual?

The manual. Tells you where specific splices and grounds are exactly. By following back the circuit to its origin you should find the problem. I'm going to keep an eye on this one if you need help or diagrams or or locations of joints common connections or splices let us know I actually have a library that has all the wiring diagrams if I can't get it online

Make long leads for your ohm meter and keep checking continuity between points to confirm there is no break in the wire.

I had a 95 Eldorado friend's car last year with turn signal problems brake light problems and parking light problems it was disaster the problem the interesting thing about it was it was multiple problems and bad grounds in multiple locations and a bad splice it was confusing because there was no commonality to the problems but I will tell you this high resistance in a circuit will cause odd things to occur elsewhere I had three bulbs in the rear light assembling that we're causing a high resistance condition which caused problems with the IPC. Always look for commonality in grounds power it will help diagnose the problem

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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You need to remove the door pass-thru conduit and check the wiring.

Remove the door panel and disconnect the connectors and retainers so you can pull the harness towards the drivers foot well after you remove the kick panel and apply the parking brake to get the pedal out of the way. Follow the wire loom to the door opening and inspect it. Almost always it is the orange (red???) that is damaged....

ALL the ones I've worked on were on the body side of the door pass-thru but maybe you'll be lucky. If not let us know and I can give you a technique to repair the wire without too much cussing.

DON'T poke holes into or probe wires with a test light or bed-of-nails tester, you're asking for trouble by doing that.

Those wiring diagrams are useless.


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