I noticed when I start my D2 my rear view mirror does a self test of all the lines in display and I can see a C and F light up as well. Is there any way to get my mirror to display the outside temp instead of the compass direction it currently shows? I almost always have my Garmin with me and I have a good sense of direction so I would much rather see the outside temp. I know the HVAC display will show the outside temp for a few seconds if I hit the button.

 

I will pay attention to my mirror, I have never noticed a self test.

 

When you first turn the key on watch the little display. You can see all the lines light up at once and you will also see the C,F and deg symbol on the display too.

 

Yeah I have always wondered that too. I thought there must be some combination holding the 3 Homelink buttons down to change it. I'm headed outside to see if I can switch it over.

 

Check out page 93 in the owners manual "Rear View Mirror Compass/Homelink.
I briefly read through it, there were no combinations using the ink pen button to reset the compass to temperature. So my guess its no deal unless its a secret combination. My guess is its a feature in the Range Rover and not programed for the Discovery. There may be the same mirror in the Rover. I have a 2003 HSE will all the options except ACE, so so if I was going to have it I think it would be there.

 

It would probably need an external sensor that isn't connected, if the circuitry is even there. It could be that's just the default LCD that the OEM company uses for all their mirrors no matter what features are installed.

 

That is not an active function in a disco, you get the ext temp from the climate control.

 

The mirror looks just like the Gentex mirrors found in many of the GM cars. I think the readout displays are all the same and the functionality changes by how the OEM orders it. Usually if the OEM wants a dual function there will be a button on the front lower frame of the mirror to toggle back and forth between compass and temp. You can always change the mirror for one with both functions, or just temp, then add an external temp sensor. I've done this before in an older GM product that did not have a compass or temp prior and it worked great. You just need the wiring diagram for the new mirror and you are good to go...

 

If it is possible with just adding a sensor, then that would be a great place to send the engine temperature for display.

 

There's a thought, that would be great!!! If anyone figures out if it's possible let us know.