Identify Vaccum Hose

[Kiqman]

There's a plastic vaccum hose that runs into the firewall on the passenger side to a diaphram looking thing with several vac hoses located on the driver's side firewall. My hose was snapped in half so I fixed it. Don't know what I just fixed though? Also, there's a wiring harness on the firewall right next to where this vaccum hose penetrates. There's a red wire in the picture that's not hooked to anything. Any idea what it goes to?

What's this vac hose go to?
What's this diaphram looking thing?
What's this red wire supposed to go to?

 

[NEK5]

not sure about the red wire but the other stuff if i`m not mistaken is the cruise control

 

[sweetk30]

yes vac switch on brake lever to kill cruise vac supply. and that red wire is for fuel pump stuff. thats the relay for pump. some old gms were nice and if you jumped one exrta wire from harnness it would over power the relay to test the pump . i have never done this or 100% sure but i bet thats what its for.

 

[Kiqman]

The vac hose I fixed restored action to my heater vents. You can see the patch I put in the vaccum hose that runs just behind the top of the dipstick. The cruise control still doesn't work but my floor/face/windshield selector works for the first time since I've owned this beast. The heater selector box must draw it's vaccum from the cruise control module pictured above? Am I getting this right sweetk30?

 

[NEK5]

hey why dont you ask me if ur right....i probably couldnt tell ya but still...lol....must be a noob thing

 

[Kiqman]

That's just the only name I could see while I was typing. And I've been a member longer but I'd say I'm the noob with about 1/7 the number of posts as you.
I knew I had fixed something - I just had to drive it for a bit to figure it out. When I started messing with the heater controls I knew right away. I could hear the vaccum working it's magic behind the dash and BAMM I have hot air coming out of my defrost vents for the first time ever. I told the wife and she was thrilled. She said now maybe I won't be such a cold bastard.

 

[NEK5]

lol

 

[sweetk30]

sorry the vac line was wrong spot for what i told ya. and the digharm thing is the puller for the cruise to hold the throtle open.

 

[Cmoe]

It looks like you have a late 80's truck.

What's this vac hose go to?
The vacume line that is on the passanger side (hard plastic), next to the AC box is the vacume switch for you air supply (Vent, floor, windshield). I thought even in the late 80's that it went to a vacume ball on the far left (driver's) side of truck. I might be wrong on later models....

What's this diaphram looking thing?
THis is used for Cruise Control

What's this red wire supposed to go to?
I dont know it's not on any of my K5's.

 

[Kiqman]

Yeah, it has the hard plastic hose going into the firewall as you can see. But, there's also the plastic "ball" on the driver's side that you speak of. I'm told the ball is a vaccum reservoir.

 

[1985_K5_Silverado]

The red wire is the "fuel pump prime connector". Refer to this wiring diagram:

88 - 90 R-V Chassis 1.pdf