Ive been looking through the service manual trying to figure out how the stock fuel level sending unit(s) get there signal to the dash.

So far ive figured they use a common ground and are wired in series with a single signal wire going to the dash. The problem is that the main unit with the pumps has a level sensor and the other side of the tank has a sub unit with only a level sensor in the assembly. They read like this

Main Sub
Full 3 ohms 3 ohms
Empty 80 ohms 43 ohms

Can I run a single sending unit in my fuel cell that outputs 3ohms full and 80 emtpy or 6 and 123 since they are in series or will I have to run to units that have the factory ranges and wire them in series?

 

you want your total resistence to equal what the circuits total resistence was from the factory.

so 6 - 123 ohms or close to it.

 

Thats what i figured. Ive never tried to tie one into a factory fuel gauge before.