I was fixing instrument panel lights and found this "box" under the dash in the passenger side.

What is it? Somekind of a amplifier? Original equipment? Radio acc?
The connector was loose and i did not find anything where to put it,
so i took this box off.

And what is the purpose of this vacuumline that goes to brakepedal under the dash?

 

The box doesn't use Packard 56 series connectors, so it isn't GM original equipment.

The vac line to the brake pedal is the vacuum release for the cruise control. The assumption is that when you hit the brakes, the last thing you want is the cruise control holding the throttle open. The brake pedal hits a vacuum switch that dumps all vacuum in the cruise system to ensure that doesn't happen.

 

Looks like a '70s aftermarket stereo amp.

- Eric

 

[QUOTE=joe_padavano;580481]The box doesn't use Packard 56 series connectors, so it isn't GM original equipment.

Actually, that is a factory part believe it or not. I know it may not look like it, especially based on the connector, but I promise you it is. Your 88 (very nice car by the way!) either has or had the factory 8-track radio. These "amplifiers" work with those radios. I've seen plenty of these in original cars, in fact I just pulled one from an original '76 98 with the factory 8 track.

 

Thanks for very quick answer!
I thought about radio amp but i was not sure.
And the vacuumline makes sense to me now

Thanks again!