Electrical No power at either power lock actuator. 93 GT

dbix11

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Aug 17, 2021
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I did my due diligence before i made an account and looked for every thread regarding power locks, switches, wires and actuators.

Power locks, switches show proper functioning.

The short of it is I purchased a 93 GT and the locks were not functioning. Took both driver and passenger side panels off. Switches are getting 12v of power on both sides. One side of the switch acts as a ground when the other is energized, vice versa.

Removed old actuator, do not believe it was seized because i could lock and unlock door with key. Actuator would not move when switch was toggled. Used my DMM and showed ~0 volts. same as the other side.

I made sure both actuators were in as the circuit must be closed for the locks to function. I undid some electrical tape on both sides and it looks like a previous owner made some test points because they most likely had the same issue they could not resolve.

My leading theory is that i must have a short underneath the dash somewhere as both door jambs look like they have impeccable wire management, most likely from a previous owner.

Help meeeeee
 
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90sickfox

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Check the connectors in the kick panel areas on both sides. Follow the wires from the door to just right under the corners of the dash.
 
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dbix11

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Thank you for the reply

I typed in my original comment "Power locks, switches show proper functioning." should have been Power Lock switches show proper functioning"

I removed kick panels on both sides and do not see anything obvious. The passenger side actuator is getting power, however the component is not actuating. The wires to the driver side actuator are getting 0 readings.

Correct to assume there is a short in between the passenger side actuator return wire to the actuator to the driver's?
 

dbix11

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I guess my question is where would my next point(s) of possible failure be in that circuit after the passenger side actuator
 

90sickfox

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This is for a 92 but should be the same.

Screenshot_20210818-141937_Chrome.jpg


You need to check connectors. There are a few. They are all the " Cxxx " numbers on the schematic. Check at the known good signal and follow it until it ain't working. The actuators reverse polarity to work. If the ground for the drivers side switch isn't working then the actuator will get power but still won't work.
 
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dbix11

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also worth noting im finding that my battery pretty much dies within 8 hours of a full charge sitting. I made sure to keep the battery voltage up after trouble shooting.

is it possible for a short that small to cause that sort of drain? Battery is new, everything was in fine working order before i started pulling guts out.

As always appreciate your help
 

90sickfox

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Yes, do a battery drain test for parasitic draw. When you hook up the meter pull fuses until the amps drop. Key off, meter on amp setting connected between disconnected negative cable and battery post. Reading should be less than 50 Milliamps or .05 amps. Most meters are only rated for 10 amps and fuse could blow if drain too high. I do a first test by disconnecting the cable and touching to post. If it sparks its pulling more amps than a cheap meter will handle ( more than likely ). With meter set to ohm, battery disconnected, check for continuity between door switch wires and ground. Only the ground wires at the switch should have continuity to ground. The power wires should not.

When the switch is pressed it supplies power and ground. Looking at the schematic you could disconnect the wiring at a connector and overlay the circuit. ( run your own test wires to the components ). Could also splice a ground to the actuator and tap power to other side. Actuator should work trying both ways. ( swapping ground for power and vise versa ).

The actuators themselves should be dead when switch isn't pressed. Meaning no 12v to them or their specific circuits. However, an issue in the switch or wiring to the switch could cause battery drain.
 
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dbix11

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Appreciate the replies, its been busy between work and hurricane.

Finally got out there for about an hour. Purchased a tone tester and unfortunately that doesn't have me anywhere closer either. I'm at the point where i feel i should just run new wires from actuator to actuator
 

dbix11

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Ok so i traced power from the passengers side pink wires: orange/black to both sides of the harness that feed into the driver's side. But still no power at the drivers side lock actuator which baffles me tried 2 different actuators and neither line shows a reading regardless of how i complete the circuit, tried all sorts of ways... this baffles me.

Passengers side showing power but of course will not actuate until the circuit is complete
 

Gs1987GT

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Did you get anywhere with your issues? I'm following this thread. On my 87, the passenger side will unlock with the switch, but will not lock. The drivers side does nothing (both switches yield the same result)


When I redo the interior, I will be addressing the power door locks. Good luck man...and stick with it! You'll get it eventually.
 
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manicmechanic007

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You need to be talking about the switches having power and working (switching power and ground to the actuator). Leave the actuators out of the diagnosis until then. The switch simply switches power and ground to the actuators. Unplug both actuators and test the switches. You most likely need to replace both actuators and probably both switches. Hit the junkyard for extra test switches. Ford only made a few styles. Car Truck all the same if the style is correct. Left and right different and 4 doors have different wiring but the same satellite switches. If both actuators work you can make them function just with your test light (put the DVOM away for this diagnosis). Switches have red white blue and green tabs in certain spots around the rectangle. Get the same ones as yours from the wrecking yard to test with. I probably have 20 -30 used switches in my toolbox just for test
 

manicmechanic007

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A good Ford tech will have a few known good parts laying around. Not perfect parts but ones that aid in diagnosis. I have a few TS switches in my cabinet and I just write on the box for instance that the high beams do not work. Then when I go to test a Lincoln for instance I will know that the switch portion works. Plug it in and if I have washer squirt for instance I simply sell him a switch. You do the same with those power locks dbix11. The actuators were a bit pricy from ford. Most last 30 years or longer. There are a hundred styles of them so find a few mustangs to rob at the wrecking yard. The plugs are the same to plug the actuators in. Find yourself a test actuator to play with too. You can spend hours and hours diagnosing one of these if you do not have a few known good parts. Stress will kill you. Take it easy and take a step back. You can do this
 
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dbix11

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Ok i was a able to tinker with it a bit today. Both switches have power and are operating normally.

The driver side actuator gets voltage when I use the PASSENGER side door lock switch but does not show any power when i toggle the DRIVERS.

So is it a possible ground issue on the drivers side or is it a short or even severed from the passenger to driver return line? Which is Pink/Orange - Pink/Black

I feel so close! i may have to take the drivers side seat out at some point if its under the dash, im flexible but feel like i could break my neck if i moved wrong down there. I have al lthese restoration parts that i want to install but cant because of this damn issue. Wondering if i should just install keyless entry while I have everything open.
 

manicmechanic007

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Yes you are getting close dbix11
Disconnect both actuators and keep testing the switches
Looks like you need a drivers side switch
Once you have both switches switching power and ground to both actuators
You can see which actuator(s) has failed
 

dbix11

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The thing is i replaced both lock switches and both actuators as i was hoping those were my issues, plus probably should have been replaced anyways.
 

dbix11

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One thing i will note is that both sides' switches have constant voltage to them, when i press either button my test light either increases or decreased in brightness(already forgot which.) Should either side of the switch whether it be lock or unlock be at 0 volts constant unless pressed? Or is it that small pulse that changes the actuators state?
 

manicmechanic007

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Okay if you have new parts and think they work they probably do
Now it's time to pull the boot out from the door and kick panel and check for broken or shorted wires
Bitchy job and the older ones like yours have better thicker wire with better insulation
Uncommon for a 93 but miles and use I fix 20 new F150's a year doing that
 

manicmechanic007

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There is usually only one or two wires broken inside the door jam boot
Real ugly job to fix the wires Marine solderless but connectors with the heat shrink
Real good terminal pliers with the crimp on the end or nose of the pliers
You can do it
You'll save yourself 2 or 3 hundred bucks
Never seen the wiring break under the carpet
The wiring should go into the main loom under the dash on the left side and go over to the right side under the glovebox and thru the boot into the right door
Not certain about that
 

manicmechanic007

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Keep going
What does the other side look like?
You almost have it
So you found no damaged wiring into the drivers door?