Nice looking 8 , I like the look of the 5 spokes on it.
On the heat issue, I also would say that it is the blend door actuator too. It is a very well known issue with the 97-98 models. The actuator rod is made of plastic and and cracks up the rod itself and can not rotate. It is a expansive job for one to do alone, requires the extraction or dropping of the whole dash.
There is a way around it though, it you pull the glove box down all the way and look to your inside left, toward the bottom you will see a gray actuating lever, to get the heat to work, take a 10-12" piece of wire and loop it around the lever and twist the wire till you have a extension of the lever. When you start the car, turn on the heat at high at first, then pull the wire towards the passenger door , the lever should move back and open the door for heat, if you leave it on high or medium high, the door will stay open as long as you need it. The wire can just hang there until next time or you can tuck it up out of the way for next time. This is a fix until you or someone else can do this correctly. The last time I had this done on my previous Mark, it cost me 800.00 in labor at the stealership. Next time I will do it over a weekend myself, now that I know what to do.