Its the little black canister above the brake booster, I circled it in red. The pics not of my car but mine has one of them. It has a vacume line going to the carb and a wire going into the wireing harnes.

Thanks in advance

 

Are you sure it's a wire and not a hard plastic vacuum line?

 

Its a single black wire running from the black canister behind the distributer and runs into the wireing harnes close to the heater box.

 

I don't think it's a wire, I had the same thing on my 82 Firebird, the one line went to the carb, other line into the harness. I believe it is for heater controls, maybe AC controls.

 

The black box thing is a vacuum accumulator. It has no wires, only 2 vacuum lines. It stores vacuum for the HVAC control doors under the dash.

One of them brings vacuum to it from the intake manifold. That one is probably rubber.

The other vacuum line takes the vacuum to the A/C control head, and is part of the A/C wiring harness. It's one of those thin plastic vacuum lines.

You need it. Without it, no air will ever come out of your dash anywhere except the defroster ducts.