Electrical Power door lock troubleshooting Foxbody

billison

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Ok. Edit with details on what does what and how to check it.

It starts on the drivers side. A black with white stripe power wire. Constant ground from the circuit breaker (metal box) on the starter relay. If it does not have 12v check the cb and wires for a short.

2 black ground wires that ground to the door.

Then 2 pink wires, one with a yellow stripe and one with a green. These are the switched signal wires. Resting both are ground, when switched one is ground and the other is power. These wires run directly to the passenger harness where the magic happens. These 2 wires supply the ground for the passenger side and let the system work.

The passenger side has the pink/yellow/green wires from the drivers side and a pink with black and pink with orange wire. The pink/orange/black are what actually lock and unlock the doors, they go down into the passenger door to the actuator, split and run back over to the drivers side to the actuator. This side works the same as the drivers but instead of sending a signal to the other harness it goes to the locks.


How to test. Start simple , use a test light, test for power at the black/white wire on the 2 switches.

Then test to see if you get power to the pink/yellow/green wires when switchesd, if not, change or repair your switch. You can open the switches and sand /dremel the contacts clean. Do top and bottom . Don’t forget to test that the signal goes from drivers side to passenger.

After that, you have to unplug the actuator and use a meter or test light at the harness. Check 2 things. Check to see if you can complete the circuit ( power and ground) from The harness, if not, then check for ground at the harness using the 12v wire from the harness , then check for 12v doing the same. One Of these should lead you in the right direction. The






Seeing a bunch of these questions lately.

Basic details. 88. Both doors were swapped out. Replacement doors were both 87-93 but I didn’t document the years. Everything plugged up so I figured that was fine.

Here is what I’m dealing with. Driver side switch will do nothing. Passenger side will unlock both sides but that’s it.

Test so far. Used a test light to confirm power do both switches. Both send power to some of the pink wires but not all.

Test the passenger side with a new motor, no change.

At the passenger plug, power is present when I press both the unlock and the lock.

Used the test light to check for power flow across the switch and it would flow with unlock but not lock.

I believe I have a weak ground somewhere but don’t know how to properly troubleshoot. Normally I would just jump wires to find the issue but I’m not sure how to do that here.

Any help? Hoping to avoid all the testing.

Specificly how would I rule out the switch without ordering new ones?
 
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billison

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I have 12v ground and power to the drivers side switch.

Anyone know if there is a way to jump the switch? That’ll tell me if the issue is in the switch or in the wiring.
 

billison

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Ok! Nothing to write home about yet. But using the link above .

But the black wire is always hot. The pink and orange is the lock side and the pink and black is unlock.

Took my spare non working switch to work, was able to clean the old switch and get it working. I now have continuity from the power to the correct wires when I hit the button.

Should the pink yellow /pink green be the ground?
 

Rdub6

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Ok! Nothing to write home about yet. But using the link above .

But the black wire is always hot. The pink and orange is the lock side and the pink and black is unlock.

Took my spare non working switch to work, was able to clean the old switch and get it working. I now have continuity from the power to the correct wires when I hit the button.

Should the pink yellow /pink green be the ground?
I believe the pinks get power when switched. One would get power in lock position, one in unlock position.
 

billison

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Ok. I know for sure all the wires. The pink/green and yellow are the drivers side lock/unlock power signal, the orange with pink and black are the drivers side.

I took apart and cleaned the connections in the switches. Both switches now send out power as they should. The drivers side sends power to the passenger side. Didn’t check the reverse,

I’m getting power down to the actuators, I bench tested them as good.

I’m not sure what else to test. In the morning I’ll see if I can get power from the passenger to the drivers side. Only thing left I can think of is to try and get the connectors loose in the door jamb and make sure they are clean and not corroded.

Unlock still works From the passenger side and that is it.

My guess is a ground on the drivers side...
 

billison

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Facebook came through for once.

The 4 pink wires are both power and ground. So to test you gotta test each or each whole you switch .

Then to jump it power to one ground to the other. I’ll have my answer tonight
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2AB50C4B-25D4-41DF-90EC-565A87B92EEE.jpeg
 
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billison

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Ok. I’m stumped. For sure have 12v to both switches , and both put out 12v when switched , but the only thing that will work is unlock to the passenger side.

Removed connections in the doors and jambs, cleaned then. Took the test light and test for power and ground at all the right spots, same with the meter.

Any clue where this thing grounds to the body?

Any suggestions?

Only change was if I added ground to the pink/yellow on the passenger side it would work on the passenger side and unlock on the drivers.
 

billison

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Dunno if this is a factor, but I can jump the passenger switch and lock and unlock both doors.

When I tried to jump the driver it just tried to short the wire.
 

General karthief

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I believe there are two ground wires that are attached to the door, not sure which one if any go to the door locks, have you checked the wires going into the door in that rubber boot? You may have some chafing in there :shrug:
 

billison

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Next step is to remove the wire wrap and see if I find anything, after that I am going to pull the harness from my old door and try that
 

billison

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Ok. I spent the night with my meter and am no further along than I was before .

Things I checked and confirmed. The online circuit breaker is there and intact.

I have 12v coming into the main power at both locks.

I have 12v going both directions from the drivers side switch with me testing ground from the door And ground from the other side of the switch .

12v goes from the drivers side to the passenger side through the correct wires.

The passenger side also sends the power out like it’s supposed to.

Both switches cause 12v to go down the pink/black and pink/orange wires that actually lock/unlock the locks.

Testing down at the connector for the drivers door, it’ll get power but only one direction and not enough to do anything

Passenger gets voltage to unlock both and that’s it.

To rule out weak power or ground i ran wires directly from the battery to the power and ground on the drivers harness with no change.

I’m completely out of ideas at this point of what to check.

I believe my options are to try different door harnesses ,

If that doesn’t do it, I believe the issue would be under the dash and I’d be rewiring thing

Edit.

I’ll do one more test in the morning.

I’ll see if I get a full 12v with an external ground vs across the connectors at the actuator. I can at least narrow it down to ground or power issue
 

billison

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Ok!!! We got something.

I decided to jump wires from the drivers side to the passenger.

Remember how when I added ground to the pink and yellow it would work on the passenger side and unlock on the drivers side? I started by jumping that one and it worked!

So I have a short somewhere in my pink/yellow wire.

Now find and fix it...

Suggestions on that part?


My guess is to start by jumping that wire to each harness connector till it doesn’t work to narrow down the short. Like right now I know it’s between the two switches, if I jump it to the harness under the passenger kick panel and it works I narrow it down right..
 
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billison

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Jumped the harness all the way back to the drivers door jamb. I original thought was correct, a short in the drivers door harness.





I figure running a new wire will be easiest.





I’m thinking I can cut the wire down in the jamb before the harness and leave room to splice, then tape/tie a new wire, and pull it through the jamb into the door, cut/splice and done... right?