Well the "wacky" readings I've been getting on my TRV fuel gauge finally/hopefully came to an end this past saturday.
I rode close to 50 miles and the "flashing empty" bar after I filled it......well got me cranky. So after cleaning both the wife's & my machines I proceeded to tear down the rear portion of the TRV. I pulled the seats - plastics - battery and removed the fuel tank sender assembly to get a look at what MAY have been the problem.

And I was RIGHT! The entire rheostat and float contact leads were "corroded" with a light GREEN buildup which looked suspiciously like oxidation on copper. Only the relay itself is a TIN based unit?
SO dissassembled the unit & I took out some rubbing alcohol and Q-Tips & went about the business of lightly scrubbing away the corrosion. When I was done with that I dug out a piece of emery cloth and LIGHTLY (very little pressure) scrubbed the float leads and the sender rheostat strips. I then gently bent the float leads so they would "push-back" more against the rheostat strips.
I re-assembled the sender and re-installed into the tank - NOTE: the big O-RING on the unit slides off to put in the tank 1st....then push gently but firmly all back into place.

I re-connected everything and did a temporary battery hook-up and turned on the key.

TADAAA! I read 1 bar under 3/4 of a tank (about right for 50 miles). I then slowly added fuel and watched the gauge slowly climb back to full.

It was about a 2 1/2 hr job from start to finish.

Now....I have NO IDEA what caused the corrosion??? I DON'T use ethanol blended fuel and the ONLY additive(s) I've used is SEAFOAM and Chevron TECHRON which I was told might solve the wacky fuel gauge readings in the first place. - NOPE - But I'll definately be changing my fuel brand.

Now it begs to question just how long this sending unit was "hanging" around BEFORE it was installed in my TRV and what conditions/climate it was exposed to. I've seen MANY posts about AC's BAD fuel gauge senders and this was MY fix. (from researching this problem on this and other forums)

I've got my fingers crossed. Sorry no pics......kinda misplaced the camera.....but I grabbed this from my PDF manual....

 

Thanks alot, I have been having the same problem with my '07 500. I don't have time for a teardown this evening, but I should be back home next weekend and I believe I can find the time. Besides, I really need to clean out from between my fuel tank and the protector underneath it. Once again, thanks for the post.