I have been looking into replacing the rear view mirror. In my Tbird the mirror is made by Donnelly and is connected to the
wiring harness with three wires into a 7-pin connector. It measures 9-3/4 wide by 2-1/2 high.
Donnelly (www.donnelly.com) makes and sells mirrors with auto dimming, compass, outside tempurature display. Their model 21000 ($219) has the autodimming mirror with compass and lights. The very helpful sales person at Donnelly emailed me a pin diagram for that mirror. It also connects with (apparently) the same 7- pin connector as the existing mirror. I believe that connecting the existing connector into the this new mirror would cause it to act just like the original as far as the lights are concerned. To activate the auto-dimming I think it would be sufficient to connect a wire between pins 7 and 1 on the connector. However, it might be useful to run the cable supplied to the fuse box because you could attach the pin 1 wire to the ignition power which would turn off the dimming circuit when the car is off. Also, there are some other optional connections to the auto-dimming feature. How those are used was not immediately obvious from the diagram.
Running the cable from the mirror to the fuse box does not look too difficult.
However, there is a problem which may be troublesome; size. The 21000 mirror is 10 in. by 3-1/2 in. That additional 1 inch in height may be too much. I taped a 1 inch piece of paper to my mirror and went for an 80 mile trip, city and freeway driving, both daylight and night. It really did not bother me, but I am not sure I wouldn't sometime be in a situation where that increased blind spot might be bad.
This may be the reason this mirror is not supplied with the car. I wonder what the size of the mirror with the Jag convertible is and who makes it. TBirdTim has connected new stuff into the fuse box. Perhaps he could give us some guidance there.
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VIN 106587 White, White, with
chrome hood scoop bezel