Wiring Question

[DieselChemist]

I replaced the metal fuel line from the lift pump to the filter today with a rubber hose. On the line itself was some type of rubber boot and a wire going into it. I disconnected this wire. Is this okay or do I need it. What is it for?

 

[Joe Mc]

On my 86 it is a in-line fuel heater, it automatically turns on somewhere around 35 degrees.