This sounds a little crazy to me. The problem in the wiring harness is not so much that the sheath needs to be insulated, it's the actual insulation which surrounds the individual wires which goes bad. The wires aren't insulated from each other properly. If you can individually add extra insulation even where possible it won't really solve the problem. It's where the wires are bunched together that's the problem. I looked at the alldate website and all I found was a TSB 91_072 issued in Nov 1995 for the airbag wiring harness.

Kuan