740 Driver Door Lock Turns But No Lock?

[Studie]

Hi guys,

My 740 having some small issues recently.
So today when I tried to lock the car, the key won't turn into the lock position. Normally if you turn it left, it will lock all the doors on the car. This time it wouldn't do it.
It feels like it's jammed. It will turn in the right (unlock) position though.
When I try to push the tab down to lock the car on the door it won't go into position but instead, it feels stuck.

Any idea what maybe going on? I sprayed some WD40 to see if it was jammed, lucky it locked but then it stopped working again...

Please advise!

 

[James M]

Pull the door panel off, inspect and repair the issue

 

[AnthonyHardy2]

I'd start with checking that the door latch is closing fully. Volvo designed the door so it can't be locked while it's open to prevent people from locking their keys in the car. If the latch is sticking that could stop the door from locking

 

[Studie]

I'd start with checking that the door latch is closing fully. Volvo designed the door so it can't be locked while it's open to prevent people from locking their keys in the car. If the latch is sticking that could stop the door from locking

That sounds like the culprit Im going to disassemble the latch and see what?s up.

 

[Studie]

I'd start with checking that the door latch is closing fully. Volvo designed the door so it can't be locked while it's open to prevent people from locking their keys in the car. If the latch is sticking that could stop the door from locking

So the latch moves freely. I tried to spray some brake cleaner to clean up the gunk in it. And suddenly the car could lock itself! Locked it for a few times then it gave out and stopped working again.

Any idea how to fix this issue? Or do I need new latches?

 

[Khrrck]

So the latch moves freely. I tried to spray some brake cleaner to clean up the gunk in it. And suddenly the car could lock itself! Locked it for a few times then it gave out and stopped working again.

Any idea how to fix this issue? Or do I need new latches?

Take the door panel off and inspect the internal mechanism. See if you can see anything flexing or binding up when you try to turn the key.

Also be sure to re-grease the latch. Brake cleaner is gonna remove the original grease and/or oil and it'll stick and wear out much faster without it.

 

[Studie]

***Fixed it!***

So the problem wasn't the wires or the internal mechanisms at all.
The latch was also perfectly fine.

The problem was that the car wasn't detecting if the door was properly shut or not. The door switch was oxidized and rusty, sprayed some electrical cleaner, and BAM!!!! we are back in business!
Not to mention the problem I was having also, was after opening the front door the interior lights wouldn't turn off. It would stay on. So I disassembled all the door switches and soaked them in an electrical contact cleaner.

Regreased everything else and while I was at it greased the electric window mechanism.

All is well and fixed!

 

[Studie]

***UPDATE****

So shortly after that fix of fixing the door switches. The lock wouldn't turn again.
Disassembled the latch assembly. Theres a little metal rod that sticks into the door and has a bit of tension that pushes down a little lever inside the electronic door lock once the door is closed. There wasn't enough tension pushing down on that little lever from the rod due to some oxidation. Re-lubed everything, took the little spring that pushes down on the rod, and stretched it out giving it a bit more tension. Voila, everything works as it should!