Fuel gauge backlighting/idiot light failed

[andrewhoover]

I was riding the other night and it appears that my fuel gauge backlighting is out.  Then I was cruising along and (while I knew I was low on gas) I ran out of gas without the low level light coming on.  The low level light works when I do the start-up test, but it didn't when I was running out of gas.  Does anyone know if the two are related?  I've checked all the fuses and they are all ok.  I am sure that both the backlight and the idiot light worked recently, which makes me think that the 2 problems are related.  Anyone with a shop manual or great systems knowledge?  I would appreciate your insights.

Thanks

[EvilBetty]

Wow that's odd.

You're fuel sending unit is still working if you're fuel gauge is working.  The bulb is not out and you don't have a complete short if you're getting the warning light during start.

Been in the rain or washed it lately?

I'd need to look at the wiring diagram to see how the relays for those lights are wired, but I think the dummy light is control by the fuel sending unit first, then the ECU.  Let's hope that's not on the fritz.

Though if it is, there is one listed on eBay right now :)

[Stretch]

It has been pretty well documented that the fuel level sending units on Tigers have always been kind of dodgy.  Perhaps in yours, the float in the sending unit got hung up and wouldn't drop low enough to trigger the Low Fuel Light.

The newer fuel level sending units are reported to be better made and more reliable than the older ones.  If you're going to cut it that close between tanks, you may want to invest in a new sending unit.

[andrewhoover]

sorry it's taken me so long to get back on here, but we've been buying a house (our first) and I've not had much free time.  

anyway, yeah.  the fuel gauge works all the time, and the idiot light works when i start up the bike.  it is possible that it was a one time thing with the light not working, but that seems unlikely.  i haven't gotten real low on gas again since to check.  but the backlight definately does not work--a bad combination when riding long distances at night.  

is there a seperate float in the tank for the idiot light?  if not, i couldn't explain the gauge still working.  as to the question about whether or not it was in the rain or washed lately the answer is i don't believe so.  i rarely wash the bike and it hardly ever rains here in socal.  however, i did wash it at some point and i rarely burn the tank down so low before refilling and i hadn't been riding in the dark for a long time.  long story short, it may have been a problem for a while but i never noticed because i always had a relatively full tank and was riding in daylight.  

is there any quick check on the backlighting or are they even connected issues?

thanks again!

[Stretch]

There isn't a separate sending unit for the light... just the one for the gauge, which in turn controls the light by way of the bike's computer.

I'm still wondering if the sending unit float hung up before it reached the 'light on' phase.  If so, and you continued running the bike, the tank would run out and the hung-up sending unit float would be sitting high and dry above the surface of the fuel, unable to send the 'low fuel' warning to the computer.

Unless the fuel gauge's ground failed, I don't believe the fuel light issue and the backlight failure are related.  And if the ground did fail, the gauge wouldn't be working at all.  It is my completely unscientific and jackleg shadetree mechanic theory that the backlight bulb simply burned out (which happens) and the sending unit float hung up.  I usually don't believe in coincidences, but these sending units do have a reputation for being quirky and inaccurate, and incandescent bulbs are prone to burning out.  Perhaps lightning merely struck twice.

You can always bench-test it.  With the ignition on, siphon the gas out of the tank (into a safe container) and watch what happens with the light and gauge.  In particular, make sure the gauge needle drops all the way down.  

To replace the gauge backlight bulb, remove the windshield, front turn signals, and fairing to expose the back of the dash and gauges.  The steps are outlined in the first few photos of the "Girly Headlight Bulb Replacement" thread...  http://tigertriple.com/forum/index.php/topic,4592 (http://tigertriple.com/forum/index.php/topic,4592)

[andrewhoover]

wow.  that's a relief.  I had no idea that the backlighting could be replaced that easily.  I thought I would have to send in the whole gauge!  I will try that and see where we are.  

With regard to the idiot light, the gauge was showing empty or nearly so when we ran out of gas.  hopefully like you suggested it was simply hung up and has self corrected.  thanks for the insights/suggestions.  I love this place!

[andrewhoover]

the link that was included was for the headlight replacement...is there an easy repair for the backlighting bulb too?  what size bulb does it take?  

sorry, I should have checked the link before I made my last post...

[Stretch]

As I said, check out the first few photos of the headlight thread to expose the back of the gauges.  The gauge backlight bulbs are right there.

[andrewhoover]

do you anybody else know what type of bulb I will need?  I don't really want to pull it all apart right now unless its a common bulb since I'm short on free time these days--I'd rather go for a ride and worry about it in a couple weeks when I can hunt for bulbs...

[M.T.]

I might be adding too much complexity here, but while you have the fairing off and the gauge lights accessible, I would strongly consider switching the light bulbs to the LED type.  They will essentially never burn out and are much brighter than stock (for those twilight sort of situations when the gauges are difficult to read)  All of this while drawing much less wattage than  the stock incandescent bulbs.  I did the switch and really like the results.

Check here:  http://www.tigertriple.com/forum/viewto ... bright+led (http://tigertriple.com/forum/index.php/topic,3368&highlight=superbright+led)

[andrewhoover]

great idea.  has anyone else tried this?  did the bulbs fall out ever as they aren't quite the same size?

[M.T.]

I was a little concerned, too, after reading that the bulbs were not quite the same size.  They turned out to be a straight swap for me though- no modification of bulb or housing.  Although the body of the bulb is a little bit smaller, the base still pressure fits into the bulb socket and the fit seems good.

I've had about 8 months with mine, and they're working great!

[andrewhoover]

do you have a part number for the bulbs?

[coachgeo]

do you have a part number for the bulbs?

lot of this kind of info is in the orginal LED thread linked a few post up.]

Just hit the link and get the info from the source.

[andrewhoover]

thanks.  I guess I totally overlooked it the first time thru.

Cheers to all!