You need to disect the harness to see where the issue is.

I agree with 1GMfan if you find a short check the same spot on the new harness for damage so it doesnt happen again (rubbing against a bracket,etc) Randy

I had fits with one motor doing the same thing. I would remove the harness, try spreading the pins and reclamp the harness only to have the problem come back a couple weeks later. Finally I used a electrically conductive grease (not the dielectric which shields the connection). The grease is metalic in color and it maximizes electrical conductivity so even with some movement the pins remain electrically connected. I know Grainger sells the stuff:

CHEMTRONICS Silver Conductive Grease

a fellow sunny owner had this same exact issue, he found the wiring harness under the pcm mount was chafing on the wiring & wore thru the insulation. I added snake wrap & some zip ties on mine to prevent.

i had the same problem early this summer. boat side was tiewrapped(tight) to control cables. not fully engaged, would work-out then remake circuit after engine quit moving from running. it would kill dash display, also. i use x-acto tool to spread pins, just enough but not break off.