Repairing the low fuel warning light.

[PPuxley]

I said Id post when I had repaired the broken fuel sender. There are actually plenty of Youtube videos covering this , but here it is specific to a 1995 M900.

I had pulled mine apart to see what went on inside and went further than required for this repair. So some of what you see in my photos is not what you will have if you follow this. I didnt photograph it as it came apart unfortuneately.

In researching this I was amazed at the arguments generated in comments to videos when people realised that you were putting a heated electrical circuit inside a petrol tank.
However this is common practice. Afterall submerged electrical pumps where the fuel flows right through the electrical parts are also common practice.
With this particular thermistor in this application it gets warm but I was able to hold it between thumb and forefinger without discomfort. It takes about 30 seconds to 1 minute to light the lamp when removed from liquid.

There is a video of it working Here
I know Im running it through the oil warning light, it was just the first one to work when I was tracing it through the plug

The photos are in an album HERE




This is the Thermistor I used

1. De-solder the wire coming through the tip cover

2. Very carefully grind off the swage that holds the top cover in place. Only grind off the minimum you need to get the cover off. The idea is to leave enough to be able to peen it over when it comes time to refit it.

3. Withdraw the cover

4. Snip off the old thermistor as near below the chip as possible to leave some of the cable to solder onto





5. Prepare the thermistor and solder onto the centre wire you have just cut. It is very important that none of the wiring below the Thermistor is able to ground on the earth of the casing. In my repair I insulated it with some PVC cable sheath (I wasn’t sure how heat shrink behaves immersed in petrol)

6. Replace the cover pushing the Thermistor wire through the centre hole, and solder in place. Make sure the other 3 radial holes are not blocked

7. Because the connection of the tip cover to the base of the sender may be compromised electrically I extended the return cable (black) to connect directly to the Thermistor return wire.



8.Carefully re-swage the cover to the base with what you left of the base swage when you ground it away. I did it resting on a slightly open vice and tapped the base over the flange of the cover. Im sure those with a lathe could find a more elegant solution.