Cadillac Repair: 1981 Eldorado MPG display problem, serial data line, engine cranks

Question
I bought this Caddie as a repair job to keep me busy and boy it does!It stays in 8 cyl.mode and MPG wouldn't display.(it sometimes only displays for a fraction of a second when the engine cranks)I followed chart 11 and the blower won't work unless wire 918 is grounded.I then followed chart 1 and installed an aftermarket control head and the blower is still dead but i can hear a click in programmer when blower operation is selected.The power module connector also ranges between 8 and 13 volts depending on which E.C.C. button i press.Serial data line pulsates between 2.25 and 4.5 volts and  E.C.C only displays '..' in diagnostic mode.Chart 11 takes me to line 451 which i have checked and found fine.I notice however that there is an A.L.D.L connector but there is no 'box' connect it to.Which components do i need to buy to make 1)the MPG display and 2)the blower working?

Answer
The first things you need are several pictures and numerous directives to test and fix this pretty simple problem.

Since this is NOT my website and it only allows 1 picture you will need to e-mail:

onlineautohelp@msn.com and repost your question.