Wowza!!! $1700 for an ECU and $600 for a harness? I'm in the wrong occupation!
What I would do... [don't we hate it when someone says that?
If you've written off the old faulty ECU, I would open the cover of the ECU unit and check each circuit on the board, especially around where wire #132 enters the box. Check for cracked solder joints, or a bridged circuit where solder has jumped the tracks and is possibly causing voltage leak onto 132's circuit. Also look for obviously burned capacitors or resistors. It could also be a dirty circuit board that a blast of compressed air and a spray with contact cleaner could clean.
A $10 Home Hardware soldering iron, [they're GREAT!!!] and a good set of glasses or magnifying glass, or a jeweler's loup, and you can reflow the solder tracks and connections to components. The fine point on the Home Hardware soldering iron is ideal for melting and reflowing the solder. Check actual ECU chip pin connections for proper seating.
One worthy preliminary step might be to try the faulty ECU box in your second machine with known good harness and good ECU, with the objective of determining if your faulty ecu box OR the Harness shorting [wire #132] is the actual problem. It might just be the harness itself with a chaffed harness from rubbing friction somewhere. The voltage backfeeding into wire #132 may have burned a small capacitor or something in the ECU box and maybe easy to replace. The replacement uf value capacitor probably costs $1.25 or less at any electronic hobby shop or on-line at Digi-key. Digi-key has an account with Revenue Canada that allows them to collect GST or HST so there is no delay on cross border shipments. Next day shipping to Canada, as in you'll get the next day if anywhere near a metro area.
If the harness is at fault with a short somewhere, I'd strip the harness and look for the bad wire, paint with liquid latex, and tape up good after drying the latex. Harness loom outer cover available aftermarket cheap. Purdy, too!
$1700 for an ECU?...I'm still shaking my head!!!
I bet they sealed the cover on the box with Phenolic resin or something. You may have to take a small cutting wheel on a dremel to cut the resin joint open. Manufacturer's don't like us prying eyes with soldering irons and electronic parts catalogues readily available.
Parts prices on some of these farming machines seem to mimic bushel prices on product. If the parts supplier sees high grain prices, the parts price inflation rises exponentially. Bastids!
Anyway, good luck and approach with determination and careful execution for a greater chance of success.
Should the problem be something simple inside the ECU box, and cheap, then while you're in there, buy an aftermarket or factory performance chip for it and wake it up a bit! A treat for your efforts!
Link to Digi-key: http://www.digikey.ca/?adpos=1t1&WT....AD3BcslsNBv9mN