cool i'll try that in the morning thanks. does the mirror come off easily with a pull. i have the pear shaped mirror housing. on another note why would anyone want to know the outside temp. whats the point

 

Ahh that makes alot of sense. Look underneath the driver side mirror to see if there is a hole with what appears to be a button sticking out. If there is just a hole then you are missing the temperature sensor. If there's a hole with what appears to be a "button" like object sticking out then you have a temperature sensor that just needs to be hooked up.

I reckon you won't have a sensor and will have to order one first.

The mirror needs to be unlocked first through using a small flat head screwdriver and pushing the tab towards (or away can't remember) in the direction perpendicular to the car. The tab is found in the other hole which is more in the centre of the mirror housing. It's confusing, but I don't know how to describe it :P
Then you can gently pry the mirror out, it should require very little force.

 

The point of the outside temp is that you can worry about thin oil when temps go up
Like Phil said use a small screwdriver to loosen the lock on the mirror. There is a locking ring glued to the inside of the mirror which needs to be turned maybe 1 cm to free the mirror.