M620: fuel light stays on all the time

Starscream · June 23, 2011, 10:01:44 AM

Hey guys, I finally put my M620 back on the road (broken wire and damaged relay), but now I've noticed something that is bugging me.

The fuel light will stay on even if the tank is full! At first it stayed on, then after a while it went off.

Now, it would stay aaaaaaaaaaaaall the way on, even on +100 mile rides.

What could be causing it?

Howie · June 23, 2011, 10:31:46 AM

More than likely a bad sending unit. Disconnect the connector under the tank. Turn key on. Light out? Bad sending unit.

Starscream · June 23, 2011, 10:35:21 AM

Gonna do that and report back the results. Thanks for your help

Privateer · June 26, 2011, 07:26:34 PM

same thing happened to me recently. same exact symptoms. used to stay on, then go off, now it's on all the time. I tried squirting some dielectric grease into the connector hoping that would magically work, but no deal.

If you figure out something that doesn't involve tearing the tank apart, I'd love to hear it. I just ignore it now and fill up after 140'ish miles.

AMITFERN · August 23, 2011, 05:42:14 AM

I am having the exact same issue... the low fuel light now just stays on all the time even with a FULL tank. Anyone know a quick fix to the issue.

Scooter Montgomery · August 23, 2011, 10:02:32 AM

Mine is on all the time, but not fully lit. For me its a short in the gauges from water damage. I do get the FUEL message in the oil temp screen though.

Armor · August 23, 2011, 02:22:17 PM

Bad fuel sending unit is a very common Ducati problem. Disconnect it and use the odometer or buy a new, expensive sending unit.

AMITFERN · August 24, 2011, 06:36:29 AM

update: rode into work today and the reserve fuel light was off most of the time. It did come on for periods of time, but did not stay on permanently. Is this a symptom of something other than the sending unit?

Howie · August 24, 2011, 10:35:06 AM

Quote from: AMITFERN on August 24, 2011, 06:36:29 AM
update: rode into work today and the reserve fuel light was off most of the time. It did come on for periods of time, but did not stay on permanently. Is this a symptom of something other than the sending unit?

Easy enough to find out. When the light is on lift the tank and disconnect the plug to the sensor. If the light goes out it is the sensor. If the light stays on the wire back to the dash is grounding out somewhere.

gfitzgi · August 25, 2011, 10:52:36 AM

I had problems with water in my dash on my 620 that caused different lights to come on at different times.

Pretty obvious condensation on the inside of the dials though. Fixed it by drilling a hole in the bottom of the dash. Problem never came back even in hard rain.

redxblack · April 14, 2013, 10:25:07 PM

Just bumping this because I have the same issue on my m900.

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M620: fuel light stays on all the time