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I have a 1984 model year. Just like any other gm product, it has those garbage colored vacuum lines in the dash for the hvac controls.
My question: How are they supposed to be routed?
There is a hard line coming out of the ecm harness. I tried pulling a vacuum on it, but it won’t pull one. There are 2 other black hard lines, which go into a rubber “connector”, one is tied into the vacuum circuit that has the reservoir on it, and the other turns into a softer gray line, which goes to the coolant flow valve for the heater core.
The vacuum supply/reservoir line T’s off and continues into another rubber “connector” with the gray line, with the other end just, there, because it was all chewed through by rodents in the past. (Please see pictures). This is all on the passenger side of the dash. On the driver side, there is another gray line that goes to the window defrost actuator, and a red, pink, and a blue line.
2nd question. What is the hard line in the ecm harness supposed to go to?
3rd question, does anyone have a diagram for this?
Since no one has helped so far I will give you what I have for an 86 with C60 manual AC controls.
So make sure you understand this is an 86 with manual AC controls.
The line from the harness is the vac supply line from the source to the HVAC system. On an 84 I do not know where that comes from. Hopefully one of the 84 guys will come in and straighten this out. On my 87 I would not be able to get vacuum (draw down test) on the supply line because it comes from the plenum / engine, too many openings to pull a static vacuum test on.
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1609160391[/url]]Since no one has helped so far I will give you what I have for an 86 with C60 manual AC controls.
So make sure you understand this is an 86 with manual AC controls.
The line from the harness is the vac supply line from the source to the HVAC system. On an 84 I do not know where that comes from. Hopefully one of the 84 guys will come in and straighten this out. On my 87 I would not be able to get vacuum (draw down test) on the supply line because it comes from the plenum / engine, too many openings to pull a static vacuum test on.
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Thank you. I did end up finding another thread about the hard line that comes out of the ecm harness, also on an ‘84, and it goes to nothing. It is just there. Several other users confirmed it is there, with no actual use.
Thank you for this diagram. You have no idea how much it actually helps.
Hvac vacuum lines
