Engine Wiring Harness '77 J-20 same as '85 G.Wagoneer?

[Luke Harris]

I have a guy who wants to buy my 1985 Grand Wagoneer engine wiring harness for his 1977 J-20. Both vehicles have AMC 360 engines. Will the 85 Wagoneer harness work in the 77 J-20?

[Bob Barry]

The wiring for the alternator will be different, if the '77 used the externally-regulated Motorcraft unit. The starting, ignition and lighting circuits should pretty-much interchange, though I don't know if the change in fuseboxes in 1979 also involved a change in the terminal locations at the bulkhead.

So, it is not likely a direct bolt-in, though the most it would take to make it work is releasing the terminals on the original engine-bay-side bulkhead connector and replacment harness and plugging the right circuit into the right place in the old connector, and rewiring the charging circuit (or even better, upgrading to a Delco alternator).

[RustyJeep]

Yes, the terminal locations on the bulkhead changed.I just swapped out my 73 harness for a 79 harness, and ended up rewirng the whole thing (because I had the whole thing). It wasn't so bad, though. It only took a day.