There are several other threads here related to power locks, but this problem seems different, and I hope easier to rectify.
Two pieces of info first: 1. I recently changed the exterior door handle. Our problem with the lock began then, but I cannot see a connection between the two yet. 2. We recently had a key made that I was using even though it was not a perfect fit. I had to force it to turn in the key chamber. I had it fixed and it now works smoothly. Could my having to force it to turn possibly caused the problem below?
So, the problem. Right now, my power locks work fine when using the inside lock button. They all lock and unlock normally by pushing/pulling the lock button/rod. My key will trigger the unlock mode, but it will neither lock the driver's door nor trigger the power lock.
My shop manual said, as I understand it, that the key unlocks the doors electronically, but that it locks the doors my mechanically locking the door, which then triggers the power lock.

Any thoughts? Clarification?

 

If this is for your 240 -
The power door locks have two simple switches that trigger relays under the center ac vent to send power to the 3 door lock and 1 trunk/cargo door lock motors. There is no door lock motor in the drivers door to move the stick down or up and unlock that door (unless someone installed one after the car was built)

1 switch is mounted inline - the black barrel on the lock stick with 3 wires coming from it. Push down, switch contacts close and send lock signal to relays. Pull it up - opposite happens. If you pull or push the stick, notice a little spring action both ways. Follow the 3 wires down to the other switch that is wrapped around the key lock on the drivers door. It's a simple slide switch, a peg in the lock moves contacts that signal the relays to send power to the motors. It's common for people using a "slim jim", the thin tool to open car doors - to grab and damage the wiring to the switch around the key lock.

" but it will neither lock the driver's door nor trigger the power lock."
Are you saying the key will not lock or unlock the drivers door? (but trigger the other doors/trunk to unlock) If so, is the linkage between the keylock and the inner door latch assembly still attached?

So maybe a disconnected linkage from the keylock to the inner latch and a broken/damaged lock wire at the keylock switch

 

The key will unlock everything normally if it is already locked. This includes the driver's door.
The key will not lock anything including the driver's door.

That the key unlocks everything would seem to rule out an electrical problem between the key and the other doors. That is, unless the locking and unlocking signal goes through different relays. I have a multimeter, but I am woefully ill-prepared to do more than rudimentary operations with it.

The quote I am puzzled about from the shop manual is this: "All doors are automatically unlocked by unlocking the driver's door. The driver's door is actually locked mechanically, but this operation causes the switching gear in the door to operate the lock motors in the other doors."

So, if I can explain my question clearly, is the key supposed to mechanically lock the driver's door, which then triggers the electrical signal to lock all the doors? If so, then my problem would lie the lever sequence between the key and locking stick. On the other hand, does the signal to lock all the doors come from the key lock itself? Then perhaps I need to replace the door lock switch that surrounds the inside of the key lock.

 

if this is a 240, both locking and unlocking the drivers door is purely mechanical. there's a pair of microswitches in the mechanism, when the lock plunger is pulled or pushed UP, one switch closes which tells the OTHER doors to unlock, and when the plunger is pushed or pulled down, another switch closes to tell all the other doors to lock.

if the drivers door is not locking with the key, then the pushrod that connects the key to the plunger is somehow out of whack.

 

Thanks for checking in, Pierce. And thanks to Hoonk, too. I forgot to say that before.
While the locking of the driver's door might be mechanical, the unlocking of it is purely electrical coming from the key switch. (I started to doubt myself, so I just went out to the car and checked. The mechanical movement from the key is only on the locking movement. The unlocking movement does not move the levers, but only works the electrical switch.)

 

However, I am starting to think that I have knocked something loose from the connection between the key switch and the locking stick when I changed the door handle. That was when the problem started. So I think the fix might be mechanical and not electrical. I'll keep looking.

 

There is not a door lock motor in the drivers door. So only the key mechanically moves the locking lever on the inner mechanism with a rod to lock or unlock the door. The passenger door works the same - but there are no switches in it to trigger the door lock motors. If the drivers door only locks or unlocks with the key, the rod may be there but could be bent so it does not push or pull far enough. On the electrical side a peg on the drivers keylock that moves with the key tumbler slides a switch to make contact - either neutral to lock wire , or neutral to unlock wire. The microswitches in the lock plunger only function from in the car - by pushing or pulling the stick against the springs inside of it. The switch simply passively moves up and down with the stick when you use the key. There are 2 relays - 1 lock, the other for unlock. Never had to replace relays - it was always the switch assembly.

You had the door panel off to replace the handle - I would guess there is a broken wire going to or a damaged switch that wraps around the key lock. The wires are flexed every time the stick is pushed up or down (leading to failure) and are easy to pull out accidentally, or a 30 year old plastic switch could be broken. If you are curious about the the door lock motors - take the passenger door panel off -

There many pictures of the door lock switch on the linked page
https://www.google.com/search?q=volv...YozBj8y1nIXyMM

 

Thanks Hoonk.
Just came in from the garage. New information. I removed the switch from around the key cylinder. If I manually move the switch, I can trigger the power locks--both lock and unlock. So I know that the electronics are working. The wires are quite frayed but it is operational and the signal is getting to the power locks. But only when I manipulate it. The problem, then, is that when the switch is attached to the cylinder, the key is not able to travel far enough to trigger the locking motion. If I could get it to turn just another millimeter, it would work. In fact, I tried this by putting in a broken toothpick as a shim to create more travel distance. It worked. The trouble is the toothpick falls out when I unlock with the key. And I would hate to be driving around with a broken toothpick keeping my lock together anyway.
The range of motion on the key cylinder for unlocking is from perhaps 12 o'clock to 10 o'clock. The locking side is only 12 to 1 o'clock.
Also, there is not problem with the stick. That is only part of the system that seems to work properly. My problem is only with the key.

Hope this all makes sense.

 

It works now. I don't know what happened, but I did three things.
1. Since this all began when I changed the handle, I thought maybe the new handle had less play than the old one. So I loosened the adjustable rod as far as it would go. I still don't see how this could be connected to the lock problem, but I did it.
2. I tried the toothpick trick again just to see if I could get a better fit. I did get it stuck in pretty good so that it would lock and unlock and not fall out. I still didn't feel right about holding things together with a toothpick, but at least I knew it would work.
3. I had been doing all this work with the door open so I could look at the insides and reach around to operate the key. I didn't realize that the door won't lock when it is open. However, the problem originated with us not being able to lock it normally from the outside with the door closed. But I noticed now that with my toothpick shim, not only did the power locks trigger with the key, but the key would continue to travel to perhaps the 2 o'clock position (see the earlier post) and mechanically lock the front door. It didn't do that before.

Just to see what would happen. After I noticed that key movement seemed to work now, I removed the toothpick and it all continues to work normally now.
I have no idea. But it seems to be done.

Thanks Hoonk and Pierce for your help.

 

So, if you have a lock problem, you go to a locksmith? Surprised nobody thought of that before!

 

Get in touch with this auto locksmith service provider, They will assist you in a better way.