sabutter, did this exact conversion myself on my 86'glhs, I refused to spend the $460 on the
S60 wiring harness that was aval back in the mid 90's. I basically took the wiring diagrams of the 40 pin of the 86' and the wiring diagram of an 89' (89' turbo lebaron was the donor).
I basically laid the entire 40 pin harness (inside part) on the floor with the 40 pin and 50 pin harness from the engine bay side. I stared at it for awhile and convinced myself that with a good soldering iron, wireloom, wire ties, I was gonna make it work. Take the simple stuff first, like headlights, windshield washer motor, fuel injectors,
TB, temp sensors and so on. You'll be perplexed as you stare at the ignition wires, like the large blue, yellow, and red, but these are the only ones that become a challenge. Just match them up going through the conversion of getting everything from the 50 pin donor to the old 40 pin plug. You'll find yourself doing a lot of splicing because of the different end plugs on some things, and you'll eliminate wires you won't use like cruise control. When you start, don't cut everything off the 40 and the 50 from the jump, take each wire at a time, be patient and it'll work for you, solder, don't use crimps. As I remember it took me awhile, but I put this back in less A/C with the 88' style
S60 SMEC, it worked. I had one issue with power going to my extenal Bosch fuel pump, so I ended up bypassing the stock wiring for it. Other than that issue it worked for me. Take a look at the pin outs on the 60 pin
SMEC, it'll help and assist, and also, it can get confusing looking at the wiring diagrams for the 40 and 50 pin harness. Not including the
SMEC, there's 4 to look at, 2 on the engine bay side and 2 on the cockpit side. Keep the 50 pin diagram in the cockpit out the picture, just my experience. When you start getting a road block, ping me, and I'll assist in any way I can. Gordon
TurboDodge.com 
