Things i have found or replaced so far are. Replaced pickup sensor in distributor, have found NO voltage at the coil while cranking or with key just on. I have swapped the relays for the asd and the a/c back and forth to see if it was that relay. Also replaced the coil wire because when I got to the truck it had popped up off the tower and rusted the terminal in it. Distributor cap is good and rest of the wires and plugs. Coil test good as far as resistance and continuity. Local dealers tell me the cannot test the SMEC. This is a friends truck that sits most of the time so, short of replaceing the entire harness is the anything that I might be overlooking or messed up? Due the SMEC's go out often? I took the cover off of it and did not see anything burnt or expolded in the gell. Where could I find a schematic for the wire harness?
Thanks in advance.

i just fixed a similiar problem. I had no power to the pick up coil, the smec (pin # 7), and no power at fuse #13 in the cab. turned out it was a corroded and busted splice in the wiring harness under the fuse block in teh engine compartment. I had to remove the fuse block, unwrap all of the tape, and found severe corrosion (green powder) and one wire totally cut from the splice. I tried to solder without much luck because i couldn't get enough slack on the downstream side of the wire. i also couldn't find a 3:1 butt connector. So i used a 10:12 butt connector, and found enough slack to pull one of the wires out and made a 2:2 butt splice. Worked like a charm and fired right up. I was ready to go out and buy a new smec so i'm glad i was able to find it before spending money uselessly. i got help from another thread similiar to this one. Hope it helps.