Man...I would love to see this work out...but I think you are going to have some obstacles that you are unable to overcome.
First...keep in mind that PWM does not change the voltage to the load. Your meter will show it does...but that is because it us unable to interpret what is going on. PWM takes system voltage, and pulses it at different frequencies to control the load. So if you are running 13.5 volts, it will be 13.5 volts "on and off" at differing frequencies to control the load. This may appear on a meter as a drop in voltage when in fact it's not. A good analogy I heard was riding a bike and pedaling as hard as you can...but only keeping a medium steady speed. You would pedal like hell, then coast, then pedal, coast, etc. The amount of effort you use pedaling (voltage) would remain constant...you would just use it intermittently. If you were to connect a PWM output to a scope, you would see a square wave.
Ok...the inputs needed to utilize this module. I don't think you need to worry about the fuel pump inputs. That module also controls that...but we don't need it. I would ignore it. What you need is the SCP data. Can you grab that data somewhere and tie it in? But the big question, are the Parameter ID's (PIDS) from the Explorer the same as what was utilized on the early Mark?
And once you have that all hooked up and accepting data, you now have a module that is programmed to match the needs of the Mark. When does it turn on, off, go to high, etc. If you can't program the module to your specific needs, you are stuck with the requirements of the Mark. That may be just fine...but I don't know either.
Finally, if you go to a 97-98 Mark module, I'm pretty sure that would utilize the Multiplexing network (CANBUS) and is of no use to most of us here. My 99 still uses SCP even though it's OBD II compliant. However, there are aftermarket companies for stereo integration (i.e. PAC Audio) that build modules for either grabbing data off a CANBUS and changing it to usable data, or putting data on the CANBUS. I wonder if it's possible there is something already out there capable of doing this switchover. Just a thought.
NICE59...please keep up the good work and let us know what you find...I am very interested in this. This module would answer a lot of questions. Also, do you think it's possible that WDS could reprogram the module if you found the software somewhere?
Oh yea...to the guy who thought it was a BAD idea to give control of the fans to the PCM (can't remember his name) ARE YOU FREAKIN' KIDDING ME????? Computer control has been the single greatest (and most reliable) achievement in automotive history. Why would anyone want to go backwards if you didn't have to?? Show me one factory vehicle from the pre-computer era that has over 660 hp, a/c and could be driven by grandma to the grocery store.