Help me help a fellow GSer with instrument cluster problem?

[bgk]

Here?s the situation:

I?m parting out a 1983 GS750ES that I bought from a fellow GS Resources member a few months ago. The bike was sold to me for parts (minus the carbs and exhaust and some miscellaneous body parts, which were already sold) because the transmission was trashed beyond the patience and financial resources of the owner. According to the owner, the entire bike worked properly until the tranny failed. The owner knew that I bought the parts bike principally for the fairing and a wheel/tire combo, and he had no reason or motive to lie to me about the condition of the rest of the bike. Paperwork and inspection sticker showed the bike was registered, inspected and on the road recently, prior to my purchase. There?s no visible evidence of a crash or electrical system burning, melting, etc.

Another fellow GS Resources member with a 750ES whose instrument cluster was broken recently bought the instrument cluster from my parts bike, mounted it on his bike, and reported back that the replacement cluster did not work either. His email did not indicate that he was angry, or wanted his money back, or anything else negative. He simply assumed that some other part of the electrical system on his bike was defective and resulted in the symptom that his original, and my replacement, instrument cluster do not work.

I?d like to somehow help him out in this matter but don?t know how myself.

Can anybody help with a method to ?bench test? the instrument clusters and/or test the connections on the bike from the wiring harness into the instrument cluster?

Is it possible that something in his electrical system could have ?fried? both clusters, and therefore I could have sent him a perfectly good cluster that is now ?fried?? This is my main concern for if/when the guy I sold the part to may become dismayed and dissatisfied.

Are there any fuses inside the clusters?

I'm starting to understand the downside of selling/buying used electrical parts for motorcycles. (I've also got an ignitor box with a sale pending, and I don't want another disappointed buyer).

I?m very inexperienced with electrical systems and diagnosis. I?d like to help this guy out.

Any ideas?

[focus frenzy]

nothing in the cluster works, or just somethings don't work?

[focus frenzy]

I don't have a diagram for a late model 750, but I do for the late model 550, it should be similar.
the fuel, temp and gas Gage as well as several of the warning lights get their power from the same wire, this wire also powers the turnsignals and the brake light.
does his brake light work?
does his turn signals work?

have them check for battery voltage on the orange wire going into the cluster, with the ignition switch on.

[bgk]

Leon,

Thanks for responding. The guy emailed me last night and told me that the problem is in the bike, not the instrument cluster. He didn't say how he figured that out.

But he did indicate that he's not in any way disappointed with my sale to him and specifically stated that he was happy doing business with me.

I can now in good conscience go and cash the Money Order he sent me, and add it to my small but growing funds set aside to go buy some new carb "boots" (rubber intake manifolds) for my bike.