Long story short, I am installing a windshield washer low level fluid sensor in my methanol tank. My previous methanol tank had a float style sensor in it, like the one in the picture below.




Now, This float sensor worked fine for years in the tank I had, but now I swapped tanks, and I wanted to go with a different style sensor because a float type sensor like I had may be inaccurate with the sloshing of the fluid in this new tank. So, I decided to go with the sensor in the pic below because its style would be more accurate in a tank like I have now. The sensor is from a 2004 VW Golf (but it is the same sensor used in many different vehicles).





Now, when I removed the old sensor, I literally snipped the two wires. One went to a ground, the other went to an LED light I have on my dash letting me know when the fluid level was low. I believe it was powered by the ignition off that same wire as well.

The new sensor also had two wires. One I assumed was for another ground, and I figured the other would work to the LED light same as the previous light did.

The problem is that when I hooked up the system last night, the low level light did not illuminate on the empty tank. I checked that the wire was getting power (and it was), and I even re-wired the old sensor up, and the old sensor set off the light just fine. But for some reason the new sensor won't light up the LED. The sensor is brand new, but the pigtail I got for the new sensor was used (but it supposedly was tested before I got it).

I don't know enough about how the sensors work to trouble shoot this correctly. The old style sensor would conduct the electricity and close the circuit lighting the LED when the float was at the bottom. But the new one is not closing the system when the two prongs are not touching fluid. I did not check if when the two pronged style sensor DID touch fluid if that would illuminate the light, but even if it did, I'm not sure how I would go about reversing that into having the light come on when the tank is low on fluid.

Anyone out there smarter than me that could shed some light on this for me?

 

You need to check to see if the sensor does conduct with the fluid, of it does you need to run it through a reverse relay. So when there's power through it, it disconnects the relay to the led, and when there isn't power it connects the relay. The relay you need is the same one used in the 3 relay set up used on 95 LT1'S for the cooling fans (relay #3, it's a 5 prong relay).

 

The sensor does conduct with fluid but it is meant to show when there is not conductivity.

The problem is I believe it needs to go through a VW/Audi PCU to operate (will not work wired to the F-body setup).