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Lost All A/c & Heat Vent Control


Bill C

My 85 has been down and out for about 10 months with a rod knock. Not to fear, rebuild time is VERY near! :) Anyway,,, yesterday I charged the batttery and let it warm up ( it still runs at 15 lbs of oil press and no knock at idel). I set the heat to high and all of the air comes out of the top AC vent. I can't get it to shift to defrost, lower vent or bi level.

I have great engine vacuum and it looks like the 7/16 vacuum line from the manifold is connected and intact. It gets lost in the maze of stuff on the fire wall so I can only ASSUME that it is intact up to the fire wall. When the engine comes out I will replace ALL of those lines.

My question is ::: Where exactly does that vacuum line come into the passengers compartment? I dont want to rip the dash apart any more than I already have to find that single vacuum supply line for the selector switch. The selector switch is also intact.

My greatest fear is that I had a MOUSE in the car for a short time and I'm very much afraid that he made a meal out of one of those pretty little colored vacuum control lines. :( Mouse:bang
Let me see what I can do to help you out 85 is bad for melting the vaccumn tubing by the right exhaust manifold. Th line comes off the check valve on the drivers dide of the distributor then over the top down the right rear of the engine then over to the A/C evaporator housing over the top then into the passthrough connector on the fire wall where the ECM harness goes through. The harness get's so close to the right exhaust manifold it melts and closes up. But instead of repeiring it by the manifold it you locate the tube as it goes around the back side of the distributor you cab splice it there and then find the other end where it goes into the pass through connector but remember there are two vaccumn hoses that go through the connector one is the one that goes in to the passenger compartment to supply vaccumn the the switching valve the otherone is coming out to the hat water shut off valve to shut water to the hearter core when the A/C is on. One way to know it's a vaccumn problem is operate the Mode lever in the car with the engine running and listen for vaccumn while you switch ever switch will hiss even a little when you work them so this should be able to prove the problem so if it's quiet then start at the check valve and work your way into the car untill you find the problem.

David Fulcher

Theres no HISS in the selector at ALL,, sooooo, I am praying that the line is rotted and melted. Let the mice eat that one!!! Rosted vacuum line, hot and crispey!! Ummmm Ummmm, come and get it you little *%&#@!*&

Thanks for the reply. I will check it out T O N I G H T and let you know what I find!


Bill Curlee

P.S. I caught the little *&)(#@%&. Had to set a snap trap in the engine compartment AND the in the interior. I had one living in both places.
That will be another post for another day " HOW DO RODENTS GET IN MY 85???

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