Where does this hose hook up to?

[SquareRoot]

What wasn't working correctly after you drove it home from the shop? That will at least tell you where to look.

 

[Jimmy84]

It looks as if it's going through the firewall. If you had cruise control on that truck at one time, it could be the cruise control vacuum break that went to the brake pedal valve. Without having vacuum operated AC controls, the only other reason for a vacuum line that size to run inside your truck is for the cruise control vacuum break. On my 84 that hose goes through the driver side firewall to the lower right hand side of the master cylinder.

 

[AuroraGirl]

It looks as if it's going through the firewall. If you had cruise control on that truck at one time, it could be the cruise control vacuum break that went to the brake pedal valve. Without having vacuum operated AC controls, the only other reason for a vacuum line that size to run inside your truck is for the cruise control vacuum break. On my 84 that hose goes through the driver side firewall to the lower right hand side of the master cylinder.

That’s why I’m thinking maybe a gauge

 

[gmbellew]

even non-AC trucks use vacuum to switch from floor to defrost, right? or do they use a cable like the hot/cold door?

 

[Raider L]

@akchevrolet,
Did this shop put a oxygen sensor in the headers? Or a bung for one? Since you don't have A/C this line could go to some vacuum source, and the engine wasn't running funky coming home? Non a/c vehicles had a cable pull for the heater and vent door. And wires could have been in this hose since it's going into the cab, to protect them from engine heat.

 

[Raider L]

Call that shop and ask them, "What the heck did you do to my truck??!!" lol

 

[akchevrolet]

Found the plug for the o2 sensor they didnt cut it. Didnt put a bung on the headers for the o2 sensor.

 

[86 SCOTTSDALE]

even non-AC trucks use vacuum to switch from floor to defrost, right? or do they use a cable like the hot/cold door?

No, Non AC trucks used cables, Bothe my trucks are non AC and I have removed the air plenum from bothe my trucks to clean out mice nests.

 

[Dave M]

Get your head/hand up under the dash and find where it goes to, simple.

 

[akchevrolet]

Get your head/hand up under the dash and find where it goes to, simple.

I was asking for the outside not inside.

 

[Dave M]

I was asking for the outside not inside.

Sure, but if you know exactly where it runs to, we can possibly better advise you as to where to connect it back up..
It may be a redundant hose.

 

[akchevrolet]

true true ill take a gander