The RS only has the red 4 litre warning light. Mine has not lit up since I've had it except on one occasion with low fuel, when it was really cold outside last winter and I was moving it from storage to the garage for some off season maintenance. Yesterday I checked continuity of the wires from the fuel pump multiplug to the dash, all ok, checked the bulb, ok. Pulled the sensor out, it comes apart a little, just a couple of wires with two diodes (?). Not sure how to test the guts of this little beauty. Any ideas on what's wrong?

You say it was really cold when it did work so I will put odds on that it is the thermistor in the tank that is supposed to come on at 7 litres. It works by a change of temp by not having the fuel to cool it, it gets warmer and then conducts enough to light the 7l light. If you can't do it yourself then any electronics tech should be able to figure it out and replace it. They go strange when they get old like me.

wish i knew what those parts were ....i have a feeling that they are using standard type diodes (which all have a thermistor/ heat reaction properties ) just what type are they ?

charlie99 wrote:wish i knew what those parts were ....i have a feeling that they are using standard type diodes (which all have a thermistor/ heat reaction properties ) just what type are they ?

Check this thread

thanks bert ...seems the only way is to look up some suitable replacements ...ntc 600 ohm at 25c

although i notice some physical conditions that could affect the operation .

the globe if wonky connections would certainly affect the comparitor operation

the connections at the back of the instrument cluster (known for bad connection) would certainly add to the problem .

tolerance drift of the thermistors (due to heating constantly ) actually wouldnt mind betting they have gone high by now , after all those years .

id be reconning that if you found one that actually works after 100,000 miles - killometers and 25 + years -- take a picture--- that would be a rare bird indeed ....giggles

Does anybody know what replacement thermistors could be used? Type or Farnell no or similar?

found this rene

http://parts.digikey.co.uk/1/1/91965-thermistor-ptc-ocp-600-ohm-25c-ym120c30n601.html

but neaarest i can find as ntc = http://parts.digikey.ie/1/1/7755-thermistor-ntc-500-ohm-25c-rl1003-312-73-d1.html

Solved. Bought a used unit off eBay, installed today, and once everything balanced to temperature (cool gas, warmer air) I have a red light on the dash. Which will be nice. I went on a ride this summer thinking I'd be ok, up and down some steep hills on the highway, as I would climb, the gas would slosh back and I'd get a bad miss, flatten out or go down, the pump would get enough gas. Limped into a fuel station and had to coast the last 50m. As soon as I stopped the bike, the engine stopped. Don't want to do that again. I'm still pulling bits of the seat cover out of my sphincter.

yay good work