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I have a 1977, on the firewall behind the right head there is a round plug? with three hoses coming out of it. The black one runs to the left side of the engine bay and hooks into the vacuum headlight lines. The green? one runs up into the cowl area and goes into a plastic screened area on right side of the cowl, so where does this go and what does it do, I am assuming it is hooked up, I will find out once I get this car running. The white one is broke off, in pictures on the internet it shows it running over around the A/C housing on the right side of the engine bay. So again, where does this line go and what does it do.
The Green hose goes to the plenum Fresh Air vacuum actuator.
If you remove the plastic trash screen (2 Hex Head Screws) the hose will attach to a hose coupling that is part of the Fresh Air door.
On the inside of the door, (you can't see it when door is installed) there will be another short section of hose connected to the vacuum actuator.
The White hose is connected to the Hot Water Shutoff vacuum valve in the 5/8" heater hose.
When you slide the COLD/HOT heater control to COLD you (should) have a vacuum signal to the White hose.
Yup,
When selector is on "Max Air" door behind that plastic screen closes and shuts off fresh air intake. Thus recirculating the air inside cabin for quicker cool down.
White line is connected to a vacuum switch mounted on heater box behind right side of dash. swinging the door closed inside the heater box to cold hits this switch at the end of the levers travel and sends vacuum to hot water shut off valve.
Thank both of you for the information, this is my first Corvette, so a lot to understand. Add in that the previous owner had started parting out the car I have had to figure out what is missing and figure out "what did this cut off wire/hose" hook to?????
Sorry it took so long to get back after you replied to my post. I do appreciate the help. I have attached a photo of the engine so you can see what I started with, none of the missing parts were included, and then they had started to pull the intake and a head. It is continual surprises.
There are a few of us here that have owned our 77's for decades, we are here to help when we can...
The 5/8" heater hose once had this vacuum operated shutoff valve installed in the 5/8" heater hose located just below the evaporator housing on your A/C equipped car.
If you can afford to purchase a Assembly Manual for your 77 it is a good investment and shows how the car was assembled on the line.
Photo of the Vacuum operated Hot Water Hose 5/8" Shutoff Valve.
If you do decide to purchase a vacuum valve sometime in the future I can assist in finding a good USA made one for you.
The aftermarket China made ones are junk...
Thanks for the advice on the assembly manual, I have a 1978 Chilton's that I bought new and now is coming in handy again.
I will keep you in mind on the heater valve though it may be awhile. I have pulled the top off the engine and the pan and no surprises so I am getting ready to put it back together. I just hope there are no expensive sounds when I start it up, after that I will figure out what needs to be worked on next.
1977 Vacuum Hose??
