Its funny you mentioned that because earlier this week I did a search to see if anyone had added a dedicated switch/button to just turn on the heated mirrors. I am not a fan of having to turn on the rear defrost in order to activate the heater mirrors. Especially after hearing so many stories of the rear window shattering while using the rear defrost. Every time I hit that button I get nervous. Does anyone know how difficult it would be to add a dedicate switch for the heated mirrors?? I am sure [MENTION=15785]J.A.[/MENTION] could shed some light on this

opcorn:
Sure you can add a dedicated switch if you like. I havent done that but from reviewing the wiring diagrams (03-05 and 06-09) it looks like you would do the following.
First of all lets review the standard operation;
Start control:
Turning the rear window defogger SW ON, with the ignition SW ON and the back door window fully closed, initiates operation of the rear window defogger and illuminates the indicator lamp for 15 minutes.
Stop control:
When any one of the following conditions exists, rear window defogger operation comes to a stop and the indicator lamp goes out.
∗ The ignition SW is turned from the ON position to either the ACC or OFF position.
∗ The rear window defogger SW is pressed ON again when rear window defogger operation is already under way.
∗ The back door window is open.
To add a dedicated switch to operate the heated mirrors only you would need to do the below:
1) Find the black with blue stripe wire that feeds into one side of the 10Amp heated mirror fuse.
2) Splice in a diode so that it would block 12V+ from going back up into the fuse and making its way to the black with red stripe wire that is also attached to one side of the 30Amp rear window defog fuse .
3) install a 12V switch with FUSE that will bring ignition based 12V+ to the black with blue stripe wire at a point after the blocking diode you installed.
4) make a mental note that the 15min timer would not operate with this dedicated mirror switch.
Good Luck!