external temp sensor replacement (A guide)

..... In progress.

I've noticed that the question has been asked alot, but the answer is usually the same.... "This has been talked about alot just use the search". The problem I've found is that when discussed in the past people say to just unscrew the bolt on the bottom of the mirror, take the plastic off and re-solder. A few questions come to mind here, which piece of plastic do you take off and which way do you pull it? I've read some people saying to prise it off with a screw driver others saying it will slide off if pulled towards you (though not mention where you are ). Hopefully this thread can stop the questions being asked over and over

I'm going to have a crack at this myself and make a guide with photos "a picture is worth a thousand words", but if anyone wants to contribute then please be my guest.









So here we are at the beginning. I'm assuming the plastic to be removed is the blue piece... With these pictures as an aid, does anyone want to hint on the direction I need to attack it?

Scim

Hi guys, great to see so many responses

I'm going to have a go at it next weekend with any luck. Seems (as I expected), there are many ways of doing this

Hi all, sorry for the delay, I didn't forget, just alot on at the moment!

Anyway, i did it so here are the pix and description as promised!

Here we go:




Basically i levered around the lower black part you can see has been removed in the picture above (Don't forget to remove the screw!). My advice is to get a screwdriver in and make a small gap. At this point you can see the clips which are holding this piece in place. With another screwdriver it is possible to push these clips in to painlessly take the piece off as shown. (There are only two as you can see in the pic, and there is still a bit of a crack as you pull it off, but just go with it)

Here you can see I have spliced on the new component:



I cut the wires staggered by 1cm to make sure there was no chance of the splicings making contact. I cleaned the wires with a fibreglass pencil and IPA then covered the connections in nail varnish to seal them. Then i added heat shrink (as pictured (don't forget to put this on before hand)) and covered each end and the whole temp sensor in non setting silicon gel for waterproofing.

At this point I discovered that the temp was now reading -5 rather than the usual -50. Better than usual, but not idea. So i proceeded to remove the door panel where I discovered the main connector had become corroded. After some cleaning with IPA and switch cleaner with cotton buds etc it was all sorted:




I've read elsewhere on the forum about people changing the sensor and this happening and this is what I found fixed the problem.

Also before adding the new sensor i stuck a potentiometer on the bare cabled to find out what resistances equated to what temperatures on the head unit so rather than spending £20 in future I can purchase a thermister from where ever for 20p instead which will do the same job

Hope that helps

Scim

PS, getting it all back together is alot harder than taking it apart!