Car is randomly locking and central locking sometimes stops

[smiths0n]

So yesterday I managed to get my central locking working, it was the resistor inside the central locking relay that had failed, so soldered that back together and they worked.

I went to lock the car via the boot, then open/shut a couple times then it stopped working. So I thought that maybe the solder had broke.

Went in the house, came out maybe 10mins later, opened the car and it didnt work, then i started the car and pushed the pin down and surprisingly it worked.

Lets add some more complex to it now, I'm driving along this morning and then realise the doors are locked, so just thought I must of knocked the pin and pushed it down, then later this afternoon I was helping my grandma into the car, had the car running with both doors open, car was trying to lock itself but because the drivers door was open it couldn't so every 20secs it kept retrying.

Then later on this evening I'm washing my car so this time its not with the engine running the car randomly keeps locking itself and i have to keep unlocking.

So what I've established is now:
Central locking now works
Central locking sometimes doesnt work to lock all doors with engine not running
key always opens all locks if they are down but wont lock if the above
with car running pushing and pulling of the pins always opens and locks all
With car unlocked after a few minutes regardless of doing anything the car will lock itself

Please tell me this is an easy fix? I've done searching but cant find anything - well I've found people will similar issues but no resolution

[Rav335uk]

Did you use new solder? or just heat u the original on the resistor?

[smiths0n]

New solder