Originally Posted by Head2Wind
The harnesses are fairly different in where the fuse box sits and other factors, like the SM does (at least in the US) not have a tach, couple other things like where the start motor solenoid is located, voltage Reg/Rec as well as the addition of the EFI plug (different than the carb'd bikes) and the O2 sensor plugs.... Oh, and there is a absolute pressure sensor that sits up in the headlight area on the 990ADV, not sure where it would be on the 990SM.
To peal out the harness like PC did, you will also be eliminating the 'nanny' features with all the which would IMO be a very good thing..... but will require doing a bit of reverse engineering to determine what signals the ECM is anticipating from where and 'faking it out' so it does not throw fault codes.
+1, this also applies to EU bikes. Most of the electronics, relays, etc, for the ADV takes place behind the headlight, fuse block in the glovebox, while these are under the seat on the SE/SM/(SD?). I belive the ECU is also in a different position, and the Battery is also located in a different place. I can imagagine it can soon become a surrealistic nightmare to get the wiring done right using the ADVs harness on the SE/SM/(SD?) and vica versa - would need lots of wiring/soldering (no-no on a dirt bike)/crimping/etc.. But it sure can be done cheaper than buying the closest-to-the-bikes-model OEM harness.
If the SD's harness is anything close to the SE harness, than it might be worth checking out ebay, as I've did a search on it and there are some offers going on there.