Blue HVAC line

[83TwoTone]

So I’m attempting to get my a/c going. The heater core has been replaced before (I didn’t do it) and while looking under the dash to verify everything is correct I found a blue line. I believe it’s for defrost? Getting ac lines Monday and going to try to get it blowing cold. Any help is appreciated on where this goes.

You must be registered for see images attach

 

[Craig 85]

Here's one of the diagrams I have. It sound control one side of the vacuum pod in the below picture. The pod in red controls the door in the red box.

You must be registered for see images attach

You must be registered for see images attach

 

[83TwoTone]

So is the port for the blue line on the inside of the box? I’d seen some pictures where it was supposed to be on the side of the pod in red but I’ve reached my arm in there and can’t find another port on it. Thanks for the help!

 

[83TwoTone]

I’m not sure if it’s related, but I also found this. Looks like the blue line would go right into it.

You must be registered for see images attach

 

[Craig 85]

The pod sits between the heater box and the fire wall. My '85 is a little different. Both nipples are exposed outside of the box. My hose goes directly to the pod.

IIRC my '79 was like your 83, I think there is a small jumper hose that comes from the pod, goes through the box and then connects to the blue hose. I sold that truck 4 years ago so I'm not entirely sure.

 

[83TwoTone]

Okay so I should be okay to connect to that jumper? Thanks for all the help man, trying to make sure it’s all correct.

 

[Craig 85]

I just realized, that could be the tan hose on the diagram. FYI this is the only vacuum pod in the system that works in two directions, thus the reason for two lines hooked to it.

Your's should look like the metal one on the left. If the hoses are hooked up backwards it will operate the blend door in the opposite direction. The black pod is the replacement/later model version for our trucks. They come with adapters to fit the smaller hoses on the metal units.

You must be registered for see images attach

 

[83TwoTone]

Yeah I have the one on the left. I reached in there and the piece I had circled in the picture is brittle so I guess I’ll be taking the box out to fix it or just hope the ac will work okay without it for now. It does have the line connected on the exterior.

 

[83TwoTone]

I ended up cutting the line I had circled shorter to remove the rot on it. I was able to put the blue line on it, then finesse it in there and get it on the other side of the vacuum pod. It wasn’t easy especially with the little room and the hole that it goes in but I got it. Thanks for all the help man.

 

[SteveLNew]

Sorry I know this is a fairly old thread, but do those actuators actually go bad often?

 

[Craig 85]

Sorry I know this is a fairly old thread, but do those actuators actually go bad often?

Not really. I've only change 1 on my last two trucks (over the last 8 years).

I ran into a problem on my current '85 where all the pods would hold vacuum, but the controller for the HVAC leaked. If course that valve is discontinued, so I had to buy a NOS controller. The valve is in the lower left of photo #1. Prior to buying a new unit, I tried to grease the rubber gasket inside like others have, but it didn't work for me.

You must be registered for see images attach

You must be registered for see images attach

You must be registered for see images attach

 

[Snoots]

49 years and no problems with the actuators. Been in Alaska, SoCal, Vegas; all types of environments. I've replaced HVAC door seals and used PB Blaster on the TEMP cable but no actuator trouble.