Power door locks inop. ...Ideas?

[sprint29]

The 93 XLT I bought a little while ago hasn`t had power door locks operating since I bought it. It hasn`t been an issue so I haven`t done anything, but now I think I`d like to get going on them.
I pulled and check and cleaned the fuse and it is okay. I pulled the master switch out and checked for power to the switch, It`s okay. I checked for power out of the switch when I activated it, it`s sending power out.
Now... I know anything`s possible, but what are the chances of ALL of the lock acuators being bad? I basically just bought this truck, and it is my first Explorer (love it) so I didn`t get to see the system die, as in one lock at a time, or all at once. Anybody got any ideas? I`m an accomplished, certified mechanic that had to retire because of my bad back. I can generally get most things done I want to do, if I can take the time I need to do the job with my disability. I like to think things out beforehand anyway, but I need to skip as many manual labor steps as I can. But what has to be done, has to be done.
Any hints will be appreciated. Thanks

 

[BrooklynBay]

I know that power windows have a feed from one switch to another. Maybe one power door lock switch is bad, and is messing the circuit up. I don't know if it uses a relay like the 2 relay set up used on alarm systems. If you have a wiring diagram of the circuit with color codes, then that would be the best way to start troubleshooting.

 

[ma96782]

My '94, 4 dr, Explorer....only has two elec. door lock switches. One at the driver's door and one on the front passenger door, no elec. door lock switches are on the back doors.

When I purchased my vehicle........the front passenger door lock didn't work. I used only the driver's door switch for awhile........it gave out after a couple of months.

I bought a new switch for the driver's side door.

BTW....the switches are NOT interchangable. Different part numbers and the locating peg is slightly different. And the elec. window switches look just like the door lock switch, except for that locating pin.....hmmmm. Maybe, IF I cut off the locating pin??? All the switches could be interchangable??? Anyway......

Funny thing about this is........I took the old switch apart, cleaned the contact points (it's a simple switch). Also, I tested the old "broken" switch, it had continuity when tested just like the new switch. So, I tried putting it back into the door......still wouldn't work.

So, the new switch was put in............and it works.

The front passenger side is still not working. I'll get around to it......eventually.

Aloha, Mark

PS...wiring diagrams can be found here:

http://www.autozone.com/servlet/UiB..._us/0900823d/80/0b/a9/c7/0900823d800ba9c7.jsp

 

[BrooklynBay]

I forgot that AutoZone had wiring diagrams on their website. Thanks for posting that link.

 

[sprint29]

Brooklyn Bay and ma96782, good ideas both, and correct. It seems it isn`t the simple circuit after all, what is any more. I dug up a diagram and there is even a splice going to power mirror switches, which work okay. ma96782, it must be like trying to bench test one of the old dual ballast resistors. The switches probably don`t cost to much. Maybe I`ll go that route and change both. Another reason I want to get them working is I want to get an alarm system and a good feature of those is the remote lock capability.
Thanks for the input. Having seen like problems before, and getting tips like these, goes a long way for a short electrical diagnosis. What with manufacturers using power control and ground control, and I`ve seen it even in the same devise circuit, tips really help.
Thanks again.

 

[BrooklynBay]

If the actuators, and existing wiring are good, then the alarm system will use it's own dual relay set up to open, and close the locks. I wonder if the GEM has anything to do with this, since it has so many things tied into it.

 

[ma96782]

The switch I got from the FORD Dealership was a little less than $22 (no tax in Oregon).

And, the switch was just some flat spring copper and contacts, housed on plastic......nothing special.......no resistors or diodes or capacitors or transistors or aything.

Aloha, Mark

 

[BrooklynBay]

They don't charge tax on car parts, or just in general?

 

[Brock94]

The wiring is a little complicated because you need more than continuity-- the two switches have to work together to reverse polarity on the lock actuator circuit. I'm pretty sure that one switch has to feed current (or ground) through the other switch for the system to work.

The window circuit is similar-- I had a problem with one of the rear windows-- it would only go down. I pulled the switches and checked for positive switching sides when I pushed the buttons and it looked OK. (I had the black lead of my meter attached to a body ground. After ripping the door apart to see if something was wrong with the motor, I discovered that the driver door switch wasn't passing the ground along to the window when pushing "up".

Disconnect the plug that goes to one of the lock motors, insert both leads of your meter into the plug and check for reversing polarity 12V when you push the lock/unlock buttons.

 

[sprint29]

Thanks for all the replies. Brooklyn Bay, you mentioned the "GEM". Clue me in on the abbreviation. That`s an idea about the alarm too, but I don`t when I`ll get one.
Well, $37.00 later, I tried the switches, no good. I do have to recheck the fuse in case I touched something and blew it, although it is a pretty simple switch change. Forgot to check that yesterday. I`ll do that and let you know. Thanks again.

 

[BrooklynBay]

The GEM module has a lot of stuff tied into it. There are a lot of threads about different problems that are related to it. Just do a search for GEM, or GEM module, and you will see a lot of stuff come up. I know that the newer ones are called a different name, but I can't remember what it was at the moment. I saw some threads explaining all kinds of weird electrical problems that weren't easily traceable. At the end of the threads, it mentioned that they were tied into the GEM (which was defective), so that's why I thought that I would suggest it. I'm not saying that it's the problem in your case, but I think that it should be looked into, since you've already tried to check your switches, and wiring.

 

[BrooklynBay]

I did some searching for you, and came across this thread: http://www.explorerforum.com/forums/showthread.php?t=154284. He had the same problem with his power door locks.

 

[inh]

not sure on your trucks wiring layout, but check to see if there are relays for the power door locks. you may have a bad one or all bad ones. Mine are located in the drivers side rear behind the panel in the cargo area.

 

[ma96782]

BrooklynBay,

Actually, OR (Oregon) doesn't have a "sales tax." So, no sales tax on food or goods or services. But, OR has an "income tax."

While WA (Washington, tax 7.9%) has a tax on goods and services but, not on food (not including "fast food" and "restaurants"). WA does not have an "income tax."

And...HI (Hawaii, tax 4%) has a sales tax on most everything. Also, HI has an "income tax."

Aloha, Mark

PS.....The government will get it in some way.......either, through a sales tax or an income tax or a combination of both (sales and income).

 

[sprint29]

Thanks again for the replies. I now have power door locks working. I decided to check the wiring under the drivers side door sill, and I found some interesting stuff. It seems a previous owner had an aftermarket radio installed. I didn`t know this, as it has a factory radio in it now. Well, it seems that they spliced into the 2 wires for power door locks, possibly by instructions, for the power to the new radio. Everything probably worked fine, but when the radio was switched back those 2 circuits were open. This was done with a decent looking wiring harness, with connectors, (no wires twisted together) and it was all crammed under the left kick panel. I reconnected the 2 wires, removed all the other wiring and lo and behold everything works. Now I had better check the factory radio installation to see if there is anything to do there.
Thanks for the ideas. It did cut down the repair time.

 

[inh]

no problem. glad we could lead you in the right direction!

 

[arcblue]

Intermittent lock problems

After I read the first post last week, I suddenly had problems with my power locks. The driver's side switch didn't work (this happened once before, a few years ago, too). So, I tried the passenger side switch, and only the "unlock" side worked. I pushed all the locks down manually and hit the "unlock", and after that, everything worked again.

Since then, this has happened several more times. Currently, they are all working again, but who knows for how long. Any ideas on where to look?

-AC
'92 XLT

 

[BrooklynBay]

Did you try to replace any of your power door lock switches, or check the wiring harness under the seat?

 

[konstan]

That`s an idea about the alarm too, but I don`t when I`ll get one.

Maybe it already has an aftermarket alarm / remote entry installed and you just didn't know about it and didn't get the remote with it. Maybe the system was installed and then pulled out before the truck was sold to you.

When such a system is installed, all the connections to the power toys are routed through the alarm/remote module. if the module is removed then the connections are broken. You should be able to look around (under the dash, most likely) for a long large connector that does not go anywhere.

I had this problem with a dodge ram once. It has a security system but I did not know about it Drove it that way for months, and then one day the truck simply wouldn't start. Hours later I found and removed the secutiry module, and was able to start it. BUT, when I removed the module, I lost power locks because they are routed through the module. One then has to short some wires in that harness so that the power locks and windows curcuits are complete again.

I hope this makes sense, feel free to ask questions if not...