I just replaced mine. You'll need to hire a contortionist to help you...
Disclaimer: I'm no mechanic, just a DIYer (and a cheap SOB)
Since you have the EATC you won't have the $20 relay that is relatively easy to replace like the manual systems have. Instead, you'll have a computerized control module, part number F5LF 19E624 AD, which Ford wants $220 for. I had no luck at local salvage yards. Luckily, I found one on e-bay for $60. There are similar modules in several other Fords and Lincolns, but they have different letters at the end of the part number. I also replaced my EATC and those last two letters do make a difference (as in blown fuses or just wouldn't work).
You'll need to remove the panel below the glove box in order to access the module under the dash. Once you do, assume an upside down position under the dash with a flashlight. Under the dash, close to the firewall you'll see the bottom of the blower motor. find the plug/wires to the blower motor and follow it back to the control module. It is mounted vertically between the glove box and the kick panel. It's a black box, about 4" x 4" x 2". getting it out was a chore - there are tabs that slide onto the bracket with little indents that you have to depress to remove it. After wasting an hour upside down I lost my patience and just forced it out. Putting the new one back in is much easier...
I didn't take pictures, but here is a link to the pic of the module itself (the one I bought on ebay). Sorry, I don't know how to post pics here...if the link doesn't work you can google the part number. Don't bother searching for a how-to video on youtube or a how-to post on this forum - there are none - even my service manual only showed the $20 relay for the manual system...
http://i.ebayimg.com/t/94-95-96-Lincoln-Mark-VIII-TEMPERATURE-CONTROL-ECU-F5LF-19E624-AD-/00/s/NDgwWDY0MA==/z/owUAAOxywCJRamCQ/$T2eC16R,!zoE9s5ne3qiBR,mCQWrHg~~60_3.JPG
Hopefully you won't have to replace the blower motor - they are cheaper, but wedged in so close to the firewall that you have to remove the carpet and insulation just to get it out, but that's another story...
good luck - BBD
