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2009 TE610 Fuel Sensor Issue

zoomdude57

zoomdude57

Husqvarna
AA Class
I have been battling an issue where my low fuel light does not come on. While I can easily revert to using the odometer; I can be a bit annal when it comes to making sure everything on the bike is in working order!

I have seen a few posts on related issues, but none seem quite like mine. K7MDL has posted an excellent description on how that circuit works and that has been a great aid in my troubleshooting.

This is a 2009 EFI model.

Here is what I have done so far:
1) Verified the Fuel Warning light comes on during the startup diagnostics
2) Removed the fuel pump and tested the thermistor. Testing shows about 1K ohms at ambient temperature and applying warm air via a heat gun results in dropping resistance.
3) With the pump removed from the tank and the ignition on I am getting approximately 10 volts to the connector to the fuel pump assembly.
4) I am seeing approximately 6mA current to the thermistor and around a 6 volt voltage drop.
5) After waiting several minutes the fuel light does not come on and temperature of the thermistor remains at ambient temp. No change in current or voltage drop.
6) With ignition on and fuel pump assembly out of the bike I can apply heat to the thermistor and the fuel warning light will come on within 30 seconds or less.

Based on the above I believe my fuel level thermistor is in working order and that the Fuel Warning light is working properly. I am thinking the 6mA might not be enough current to heat the thermistor and based on what I have researched my thought is that overall resistance in this circuit is too high and thus the low amps. I know there is a 68 Ohm resistor in the circuit but have not been able to locate it.

So few questions:
1) Where on the 08/09 EFI bikes is the 68 Ohm resistor located? I am reluctant to start cutting wire harness tubing without having a good idea on where to look.

2) Is the 6mA in fact too low to heat the thermistor?

Any help is appreciated.
 
why do you need the light to turn on? keep your fuel tank full at all times.Its good for the fuel pump as well... :D
 
I have the same issue, no low warning light. Just watch reset and watch the trip odometer and occasionally look in tank.
 
Would be great is someone knew where the resistor was in this circuit. I suspect the resistor is bad or a faulty connection. Everything else checks out on my bike. Agree tripmeter is an option, but would still like the indicator as extra insurance.
 
hey there fellas, i have a sms630...fuel light is always on..i have been having fuel pump problems. some times not priming, therefore not starting. i fitted a new pump last night but the light is still on?? i thought the sensor would be in the pump?
 
In case anyone is still interested in 2020, this is what I found while chasing a non-working fuel warning light on a 2008 TE610 EFI, with symptoms very much like the ones described by zoomdude57. In my case the culprit was the 68Ω resistor, which was apparently toasted. Read on for more details.

zoomdude57 said:
I have been battling an issue where my low fuel light does not come on. While I can easily revert to using the odometer; I can be a bit annal when it comes to making sure everything on the bike is in working order!

I have seen a few posts on related issues, but none seem quite like mine. K7MDL has posted an excellent description on how that circuit works and that has been a great aid in my troubleshooting.

This is a 2009 EFI model.

Here is what I have done so far:
1) Verified the Fuel Warning light comes on during the startup diagnostics
2) Removed the fuel pump and tested the thermistor. Testing shows about 1K ohms at ambient temperature and applying warm air via a heat gun results in dropping resistance.
3) With the pump removed from the tank and the ignition on I am getting approximately 10 volts to the connector to the fuel pump assembly.
Click to expand...
I was reading the same value, and the 10V measured at the connector's white/yellow cable is the voltage at the dashboard terminal and a good indication that the 68Ω resistor is gone.
4) I am seeing approximately 6mA current to the thermistor and around a 6 volt voltage drop.
5) After waiting several minutes the fuel light does not come on and temperature of the thermistor remains at ambient temp. No change in current or voltage drop.
6) With ignition on and fuel pump assembly out of the bike I can apply heat to the thermistor and the fuel warning light will come on within 30 seconds or less.

Based on the above I believe my fuel level thermistor is in working order and that the Fuel Warning light is working properly. I am thinking the 6mA might not be enough current to heat the thermistor and based on what I have researched my thought is that overall resistance in this circuit is too high and thus the low amps. I know there is a 68 Ohm resistor in the circuit but have not been able to locate it.

So few questions:
1) Where on the 08/09 EFI bikes is the 68 Ohm resistor located? I am reluctant to start cutting wire harness tubing without having a good idea on where to look.

2) Is the 6mA in fact too low to heat the thermistor?

Any help is appreciated.
Click to expand...

I didn't measure the current in my case, but spotted the bad resistor in a different way. If you have a look at the wiring diagram, the 68Ω resistor lies between the brown wire at the ignition switch connector, and the yellow/white wire at the fuel pump connector. This is the only link between those two wires, so if you use an ohm-meter between the ignition switch connector and the fuel pump connector, then the resistor is toast. With the resistor gone, the thermistor is "powered" only by whatever comes out of the dashboard terminal that is used to measure whatever it is that it wants to measure. This current is apparently not enough to cause any significant heat build-up (my measurements with the working circuit showed a 100mA current when the thermistor heated up and its resistance fell to 60-70Ω).

I never managed to find where the resistor is actually located, despite cutting away the shrink tubing at the point where the front and rear looms meet. It must lie somewhere in the fore part of the loom, but this is of little importance if the resistor has failed (at least when it fails open and not with a short-circuit). Rather than try to locate the resistor, I spliced the brown ignition switch cable and the yellow/white dashboard cable at the forks and installed a 68Ω 2W resistor between those two right behind the headlight, where it's also more likely to get better cooling (and thus more likely to survive).

I put everything back together, tested it with an empty tank that I subsequently filled and it seems to work as it should.
 
apoikos said:
This is the only link between those two wires, so if you use an ohm-meter between the ignition switch connector and the fuel pump connector, then the resistor is toast.
Click to expand...

This should actually read "..., so if you use an ohm-meter between the ignition switch connector and the fuel pump connector and find an open loop, then the resistor is toast".
 
Reviving an old thread... I get 64ohm resistance across those wires but when powered up I get -650 on the meter. Does that make any sense to anyone? I have Baja Designs Squadron LED lights fitted. I can see the brown also powers part of the headlight assembly so I wonder if that is messing with it as I would think the filament bulb would add something.....

Anyway I do get a light now (fuel pump is out of the tank) right after it primes but then it goes out about 20 secs later (during that phase it seems like I get -850 falling to -650).

Anyone offer any pearls of wisdom? :)
 
Mine wasn't that unfortunately. Turned out to be the actual "sensor" that was gone... Looked at replacing it. Seemed to be a PITA & I have a safari tank I can see through so.... :)
 
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