Hi there. After my front door latch froze open I poured hot water over the latch to defrost. But since this the dash light says my door is open and the interior light stays on. I have to turn it off manually. Plus I cannot lock the car with fob. Have to do the three manually then the drivers door with key. Any ideas what I have broke with the water?? Silly thing to do now I think about it. Help please. Help.

Never ever had it freeze even at minus 10 you have got water into the system unfortunayely you may have to just wait for it to dry if its a mk1 1.5 open the door and youll see 3torque screws remove the top one closest the driver seat and spray wd40 in and downwards at a 45 degree angle replace screw and give it an hour then retest

Hi there. It has now been about 4 weeks. It is the mark 2 focus. Tried the wd40 into the latch. But not through the torque screw hole. Will try this when light and dry. Thanks.

If that doesnt work and you have the radio code disconnect the battery for 30mins to reset the system if that fails its a dealer trip

I was gonna try that but didn't know if it would reset anything else. I have the radio code. I will try it. It won't damage anything else would it?

All you may do is reset the ECU which may mean that the car will need to relearn your driving style for a bit.
Give the car a good high rev run along an A road to get it all balanced up again.

Thanks to all. I will try these suggestions. And then report back. Thanks. Fingers crossed.