The controls function, air goes from bottom to windshield as supposed to according to setting but air stopped coming out of the dash vents. Happaned right after I was changing settings and hear a plastic rattling noise tic tic tic clack clakc. This is when dash stopped blowing air. Inspected vacuum diverters, they all excep one change position as settings are changed. The one that does not move, when moved by hand will supply air to the dash vents. Inspected vacuum lines to the vacuum junction, It has 5 lines and 1 plug. Since 4 out of 5 lines work and the line itself is good I do not think it is a vacuum issue. The diverter that does not move is all the way on top behind the dash, can't get to clip to remove it. Any tricks on how to get to it?
Ck to see if the mode vaccum actuator is getting vaccum, you will need to test actuator with a hand held vaccum gun, if actuator has failed you will need to replace, if actuator holds vaccum and it does not move the door your door may be out of position inside case or something could hold it locked in position. you will need to check door by hand to see if it moves freely.
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Thanks gm-tek 561, I have more info since I posted. I swapped the floor and dash vacuum hoses at the valves, now the dash blows, the floor does not. I am back to the vacuum control unit now. How do I remove it? Seems I have to drop the dash completely to get at it. Is this correct or is there another way? Also, the heat/AC control panel's display was out when problem happaned. Power resistors solder let go. Fixed it first, now display operates. I'm an electronic guy, this I could fix. The vacuum distributor also has a PC board in it, I see it from the holes in the assembly, but so far could not get it out for testing.
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