I need some technical help, and please don't beat me up for not having the Bentley Manual handy, we just moved.

The rearview mirror in our 2001 A4 Avant is having auto-dim issues. Specifically it gets dark everywhere except in the middle where I need it to, so obviously I need a replacement. Fortunately it's not dripping all over everything. I'm not interested in spending a fortune on a new mirror, so my first instinct was to look at the junkyard for a cheap working unit.

I found a mirror, but it's not exactly the same as the one in my car and there are a couple of issues involved.

First: Before I go to a bunch of trouble replacing it, the "new" mirror has a compass in it. My car does not have a compass, will the compass in the new mirror work? Also, since they are not exactly the same mirror, are the plugs interchangeable, in other words, is the new one a direct plug-in replacement? The new mirror has a bunch of information on the back of it, none of it is labeled, but a likely ID number is GNTX-209, molded in small print on the back.

Second: If this mirror will work, it appears that I need to get the old mirror assembly off the windshield because the wiring for this mirror runs through the ball socket and up through the windshield mount. There is no way I can see to get only the mirror off without cutting the wire. Is there a way to get the old mirror off without breaking the windshield?

Anyone have another recommendation?

Thanks in advance.

-John