78 280z Fuel Tank Sender

[Challenger]

Having my tank cleaned so I figured Id clean off the sender and get it working again. There is a power and ground going to the potentiometer and then a third yellow wire that goes down to a small metal canister with a very thin wire in it.

 

The small wire inside the cylinder was broken so I assume it didnt work but what does it do? Couldnt find anything in the chiltons. Is it for the low fuel light possibly?

[TieFighter88]

Having my tank cleaned so I figured Id clean off the sender and get it working again. There is a power and ground going to the potentiometer and then a third yellow wire that goes down to a small metal canister with a very thin wire in it.

 

The small wire inside the cylinder was broken so I assume it didnt work but what does it do? Couldnt find anything in the chiltons. Is it for the low fuel light possibly?

 

I am cleaning out my sender from my 78 280z also, and would like to know what that little metal canister is for also. My wire inside it was broken 2... I'm trying to identify why my sending unit is shorting out my system... blowing fuses when I plug her in...

[TieFighter88]

Hundreds of views and not one post?! Wow...

 

The little metal canister at the end of the yellow wire down the long arm of the fuel-sender is a:

 

Thermistor: Used to detect low fuel level in the tank. Current flows through the wire, and the fuel keeps the thermistor unit cool... when the fuel is too low to immerse the unit, the wire heats up, and triggers the low-fuel light in your dash...

 

My Thermistor was shorting my lighting system; the little wire in the unit (if broken) will short out when immersed in fuel, and blow fuses all day... I just cut mine off, pilots don't need a low level fuel light...