Electrical 1990 lx driver side door actuator inop??

[oneowner1990stang]

I've never posted anything on any site before but here goes...
My 1990 mustang lx driver side door actuator doesn't seem to be getting any power. Both the drivers side and passengers side actuator are brand new. The passengers side actuator works perfectly. The drivers side doesn't make a sound when I hit the lock/unlock switch. If I take the drivers side actuator and plug it into the passengers side connector it works perfectly as well. Whichever actuator is plugged into the "passenger side" connector can be locked or unlocked from the either the drivers side switch or the passengers side switch. If I plug either actuator into the drivers side connector nothing happen when I hit the switch.
I'm unsure where I go from here... Any ideas?

Thanks in advance
Ed

 

[General karthief]

I'm going to guess you have power to the switch because the right side works from the drivers door switch, right? You have a break in the wires for the drivers side, or the plug at the actuator, check the plug with a test light.

 

[oneowner1990stang]

Hi Karthief, thanks for the quick reply. Yes, I'm guessing there's power to the switch but I'm not the best with electrical circuits. I was actually fearing a break in the wires.... I don't have a test light but I do have a multimeter. Do you know what voltages should be at which wire? Or would there be 12 volts to either wire depending on whether or not I'm pressing the lock or unlock? Would I place the positive probe into one wire and ground the negative then hit the switch?

 

[General karthief]

Would I place the positive probe into one wire and ground the negative then hit the switch?

Yes, make notes on what wires have power. Un plug the actuator and the switch, take a jumper (power) wire and see if you can detect power at the actuator plug, that will help tell you if your wire is broken, thats a simple minded way of checking, if you know how to check continuity with a multimeter then your one step ahead of me, I'm easily confused.

 

[Mustang5L5]

Wiring diagrams for 1990.

 

[Mustang5L5]

C222 and c221 are located in the kick panel areas

 

[Mustang5L5]

Have you actually tested for power? The aftermarket actuators suck so bad I've seen them not work unless given a solid 12v+ of power. The voltage drop from pass side to drivers side alone might be enough where it doesn't work. You'll need to actually check for power.

I got frustrated with my aftermarket actuators I threw them in the trash and bought NOS actuators.

 

[oneowner1990stang]

Holy smoke batman... Those diagrams are awesome but it's like reading hieroglyphs. lol... I'm gonna try to follow them. When I checked for power I saw around 11.2 volts but I may have been checking it wrong. What are NOS actuators? The ones I got were el cheapo brand I believe made in the finest manufacturing plants in China with a quality control second to none. ;-)

 

[Mustang5L5]

Nos= new old stock aka OEM ford

If you are getting 11.2 volts, you do have power then at the actuator.

The question then is is the actuator bad or just weak? The China actuators I bought wouldn't work with the car off. Needed to start engine fir it to work.

 

[oneowner1990stang]

ok... here's what I've got so far. At the drivers side connector (that plugs into the actuator) are two wires: pink w/orange stripe and pink w/black stripe. Here are the results. Actuator not installed, just testing the wires

pink w/orange stripe: Hit lock button and get 11.05V, Hit unlock button and get 0.8V
pink w/black stripe: Hit lock button and get 0V, Hit unlock button and get 0V

I don't know if the actuator needs to be installed to see any voltage on the pink w/black wire????

 

[Mustang5L5]

the voltage will switch wires depending on lock or unlock.

Sounds like pink/orange is the unlock power wire and pink/black is the lock wire. So when you have voltage on one wire, the other one becomes ground.

Try it with both switches to rule out one going bad. They work together to switch grounds and hots.

Since the pass side works fine, I'll assume the switches work fine and do what they should be. If you notice the passenger door actuator gets fed first and then s splice and two connectors send power to the drivers side actuator.

What you'll want to do is open the two kick panels and look for c221 and c222. Both are gray, 8-pin connectors and you'll find the two pink wires in them. You'll want to test here to see if power is making it across to the other side

 

[oneowner1990stang]

Got it. I'll give it a try.
I was trying to follow the diagram you posted and it kinda looked like the ground path flip flopped depending on whether you're locking or unlocking... seems like a weird setup but I guess that's normal for car door locks. Electronics and electric circuitry are definitely not my strong suit.

By the way, what book are those pics from. Seems I may need to go pick one up, or see if it's downloadable to an iPad.

 

[Mustang5L5]

It's a ford EVTM (electrical and vacuum troubleshooting manual) for a 90 mustang.

I have a few years, and have snagged originals off eBay for around $20

Rockauto.com sells reprints for about $20 (center book)

 

[oneowner1990stang]

I remember the old Chilton's books from when I had a 1967 mustang. Thanks for all the info. It looks like I have continuity from the passengers side door to both sides of connector c222(passenger's side) but I can't reach connector c221(drivers side). There doesn't seem to be continuity from connector c222(passenger's side) to the drivers side actuator. I was wondering if I could just splice a new wire from connector c222 all the way to the drivers side actuator??? I guess it would just be a 10 or 12 gauge wire running in parallel to the original wire. What do you think?

Thanks

 

[Mustang5L5]

WHat I'd probably do here is stretch a wire across and temporarily connect the two harnesses to each other to confirm that the actuator works like that. If it does, then I'd try and poke around a bit and see if I could find the break. If I couldn't, I'd just run a new wire and cut and solder it in place and call it a day.

 

[oneowner1990stang]

Good call! I'll give that a try tonight. With any luck it'll work and I'll have a workaround for the drivers side door lock.

Thanks

 

[oneowner1990stang]

So I temporarily inserted one end of a wire into connector c222 (passenger's side) and connected it to the correct terminal of the driver's side actuator and I was able to lock and unlock both the passengers side actuator and the driver's side actuator. So, if the original wire is broken somewhere in the bundle I think it would be best to cut that connection at the driver's side actuator plug and run a new wire back to c222. That will ensure that the broken factory wire doesn't arc across the break and maybe cause a fire. What do you think? I just don't know if that factory wire goes anywhere else besides the door actuator!

It's gonna be a pain to get a new wire through that boot between the door and the body. Argh!

But progress is being made!

 

[General karthief]

It may be in the boot where the break is, that flexes there a lot

 

[oneowner1990stang]

Yeah, that makes sense. It would be really odd if it broke where there's very little movement. Is there an easy way to tackle that boot? Is it press fit into the door and body or is it attached with screws or clips or some other ingenious way of securing it? lol. Am I going to have to take the door off? Man I hope not!

Thanks

 

[General karthief]

You don't have to take the door off, pull the kick panel, unplug the connectors, its been a while but no bolts or screws for the accordion boot.