2008 TE-510 Low Fuel Light not working

Bumping up an old thread in hopes someone can help. Have been working on a refresh of the fuel system in my 08 TE450 after it sat too long and the in-tank hoses deteriorated and made a black mess - new pump, submersible gates fuel line, new filter (Duralast FF3330DL), new prefilter screen (making due with a Airtex FS175 which requires cutting off of the black adapter on the old screen and gluing, let me know if anyone has found a better replacement), blowing out injectors, etc etc.

My problem: the low fuel sensor wire (the one into the top of it) broke off right at the sensor. Can this just be soldered back on with a dab (not sure there's much there to get ahold of) or has anyone found a replacement? Thanks for any help.

You should be able to resolder it.

Thanka. will give it a try this weekend and see how it works out. I've got a second TE so can check resistance against a working one. Is the idea that it changes when submersed or is something else going on (perhaps a float?).

my 310r works with a float (and a reed switch I'm assuming) but your '08 uses a thermistor (a resistor that changes resistance with temperature). Here's drrags explanation:

http://www.cafehusky.com/threads/ca...dicator-light-go-on-sooner.83286/#post-570138

Thanks - that's helpful background. My concern is whether I can simply attach the wire to the center of the thermistor with a dab of solder or whether there is a specific lead that's now sheared off and I won't get a good connection. Will attempt and report back. Of course, not sure sure how I will know right away as I don't know what the resistance is meant to be in and out of gas. Has anyone ever sourced a replacement - perhaps from a place like Digikey?

did a bit more digging that may be helpful to others. Turns out the silver canister is a mini bucket to hold gas and the thermistor is within (this way the thermistor doesn't constantly plunge in and out of gas when the gas sloshes around in the tank).
Fair bit of info out for lots of different auto/bike applications if you google "thermistor fuel sensor" but tough to find a source for the replacement unit.

then i stumbled on this:
http://www2.cougarpartscatalog.com/fm-ef008a.html

Low Fuel Sensor / Thermistor - Repro
Fits: 1967 - 1973 Mercury Cougar / 1967 - 1973 Ford Mustang

havhave ordered one (about $15 with shipping) and will let folks know if it works.

you're gonna hafta solder a ground wire to it, it looks like. Also it'd be nice to know what resistance/temp values it uses... stuff in the '70s tended to be much higher currents than modern stuff

(silver canister: yep)

thanks for the research. Could you measure the resistance of the old & new thermistor if you get a chance?
keep us posted.

how come you're not trying to repair your stock one? should be straightforward.

i am going to try to repair first but i don't see a lead coming out of the top to which i can solder the wire. as i understand it, there is a small thermistor within the canister, one leg goes up to the top of the canister, the other appears to be soldered to the center of the bottom - hence our ground wire just being soldered to the exterior of the canister. so if the positive lead snaps off it may be down in the canister - i don't think there's an easy way to pop the lid without damaging things - looks like its crimped in place. Top of mine looks to be just an empty small hole...

you got nothing to lose by trying.

the crimp should be no problem- go slow, pry up a tiny bit, move on around, lather, rinse, repeat until it's all the way up (use another flat screwdriver as the fulcrum so you don't break the disc). I imagine that there is a fiber/resin disc in the top that the top lead threads thru- for insulation and support. whether it's permanently attached (glued or crimped) or it's just floating, I guess you'll find out.

actually, an ohm meter will tell you right away if you got any conductor you can solder to without this "can opening" excercise.

and as far as soldering a ground to the new one- yeah, I understand what's going on.... I just wanted to make sure YOU did.

btw, some metals do not accept solder without a lot of hand-waving (etching, special fluxes, special solders etc) so be aware that you *might* have a little drama with the new one (besides the fact that it may not be in the resistance range you need).

it's worth it to try to fix the old one (and if you do: add support or strain relief to the wires 'cause they should never break). hell, it might be fairly easy to put a new thermistor in there or even make your own "can" too. if i did this (and i dig projects like this even though my success rate is probably less than 50%) I might consider potting the thermistor in epoxy ('cept the device itself), with drain holes for gasoline to egress/ingress, for additional support. and a slotted tab so I could adjust the "low fuel" level. and another idea is to... ....uh, shit- sorry. I get carried away sometimes.

if you get adventurous, drrags has a circuit designed using quad 741 op-amps (although I would've used a comparator here, I think) that is pretty adaptable to just about any sensor.

good luck. let us know what you find out.

Hey- does anyone know the voltage across the thermistor [on an empty tank]? I'd guess 5v or maybe less? [I'm pretty sure it isn't 12v: the one I have on an early style pump went in to thermal runaway, which I didn't catch in time.... poof! I did have fun watching the resistance go down at an exponential speed though]

so anyways... if anyone has the voltage across that thing- please LMK.

ps- the key has to be on or the bike running for this super-simple measurement.

Hey trench! Funny running into you here! I'll update the other thread, but good news for me- it was a broken spade on the fuel pump. Also broken is the connection at the thermmister. I have a raw IMS tank that I can see gas level on so IDGAF about a low fuel light- I'm unplugging the thermister. Now I just neeed to research on which replacement pump to get....

ps buddy, voltage across thermister is full 13.25

thanks a bunch. I'm a little remiss in mentioning to take the voltage on an empty tank.

voltage reading was taken at the harness connection

anywhere along the plugged-in wire (and the closer to the thermistor, the better) ...on an empty tank or even with the fuel pump plate out of the tank totally.

Well it turns out the thermister wiring inside the tank was brittle broken so that was unachievable.....

wow- timely: I'm repairing one (well, it's one of 20 different projects) right now. I got 5 thermistors for $0.99 on ebay. ...so- got a picture of the broken lead for me?

In addition to the red wire being broken clean off, the black wire which is insulated-coated-or covered totally different than other wires was broken inside its insulation. So although it appears to be connected o the thermister, inside its black cover, the braided wire strands were not connected. Overall 3 of the wire connections associated with the fuel pump were broken.

Did you get it figured out?