K1100LT ECU problems

[YoungEngineer]

Been having some very strange behavior from the bike recently. For over 6 months the temp warning light has been flashing faintly on and off at a very rapid rate.
Any attempt to read any errors from the ECU no longer functioned. ECU was totally unresponsive,  I thought I could live with this however as the bike still ran just fine.
However, recently, the ECU has been going into fan test mode. Temp warning light goes on and fan starts to run, even when dead cold. This is usually only when the bike is not running and ignition is on. Bike is then almost impossible to start almost like the fuel or ignition has been cut. Kill switch seems ok as my fuel gauge is still on and fuel pump can be heard.
Any ideas?

I've been offered an ECU from a K1100RS for £20 which is so cheap it may be worth a try. My question is, would this work for the LT?

[bizzaro]

 :hehehe You know how to test your fan right? You ground pin one of your diagnostic plug under your seat, turn on the key and disconnect the ground.   It sounds to me  like it is going into test mode on its own, which to me says it is grounding out somewhere.  Try switching out the relay with another and see if it goes away.  If yes, get a new relay. That is just a shot in the dark. IF that doesn't work, make sure your diagnostic one wire is not grounding out somewhere!(or any of the diagnostic wires)

[Scott_]

1st thing I would suggest is open and clean all of the electrical connections and switches. DeOxit electrical contact cleaner will be your friend.
Ignition switch, Kill switch, ECU multipin connector, the main frame ground point under the fuel tank, the ground wire connection at the starter, any intermediate connectors, plug in relays, air temp sensor, water temp sensor,...... you get the idea, as much as you can access.
Pull the starter and check the brushes and carbon buildup.

As far as a replacement ECU, the fich part #'s are the same for the RS as the LT, so long as the type is the same. Meaning with or with out Catalytic converter. Still doesn't mean that the internal program is the same, just that they use the same programmable base control module.
Inge may know more about that......

[YoungEngineer]

I will do as you have both mentioned. However I must say that it would not be the first time doing this. Thanks for the advice.