Electrics: 850: Deadlocks and car unlocking itself

[AndyPants]

Over the winter my '96 850 developed a bit of an annoying problem where sometimes, whilst the car still locks fine (including flashing the indicators), it appears to fail to deadlock afterwards (with a second flash). Unlocking and then relocking the car occasionally results in it locking - unlocking - and then relocking again the latter two without touching the fob buttons!

Since its got warmer the problem doesn't happen quite so often except the car has now twice randomly unlocked itself 3 days or so after it was locked... Opening the door results in the alarm going off, until silenced with the fob.

Now in November I took off the door card and replaced the door strap and from doing a bit of digging I read that there is a switch that might need lubricating? Is this something thats easily accessible (albeit once the door cards removed)? Or does the door lock have to come out, which I imagine would be a bit of a ball ache... Any advice would be appreciated.

Probably also worth mentioning that my interior light and door light appear to behave fine.

Last time I followed this excellent guide:
http://www.matthewsvolvosite.com/int...oval-pics.html

[SHI]

If the doors aren't fully closed, the locks will go down but it won't deadlock. So it looks like you have microswitch problem.
I lubricated mine but it made little difference. They all work freely but if you close the door gently the footwell light stays on and it won't deadlock.
Plus I have a rear door that doesn't deadlock even though the others do.

[AndyPants]

Originally Posted by SHI

If the doors aren't fully closed, the locks will go down but it won't deadlock. So it looks like you have microswitch problem.
I lubricated mine but it made little difference. They all work freely but if you close the door gently the footwell light stays on and it won't deadlock.
Plus I have a rear door that doesn't deadlock even though the others do.

Thanks, might be something to try when it gets a bit darker, I'll try gently closing it and see what happens with the footwell light.

My 760 had an interior light issue on the passenger side with a microswitch (when the interior light came on only for a split second), I got a replacement swtich from the scrappys but in the end with a bit of use it cured itself.

Suppose it'll be off with the door card again... (and a hope for the best!)

[AndyPants]

Well being impatient I just checked the door by shutting it gently and the door footwell and end lights go off fine. I also tried locking the car with me inside and naturally it deadlocked fine (checked all doors), thankfully the fob let me out again Also checked the petrol flap lock and that seems to work fine too.

After writing this I just realised I haven't tried the boot, wonder if that again has a microswitch somewhere.

Might leave it for the time being unless it becomes more consistent and add another item to the scrapyard spares list!