David, on the first picture "graphic.jpg " it shows a vacuum actuator for the defroster / bi-level and /heater defroster. it has a red vac line to it. inside the box it is attached to a door and it looks like there might have been some linkage to another diverter door inside. some well meaning but incompetent do-it-your self mechanic has modified it with various parts not found on GM products (wood screws and plastic clamps) when the A/C blower kicks on the RH door slams shut and the air flow to the dash amost stops. I am almost tempted to find a truck parked and open the doors and look inside his. (almost) thanks
I understand your problem. sounds like someone jerry rigged the problem. You may have to pull the box and investigate the problem for a way to correct it properly. Does the vaccum switch on the temp. slide control look molested.
the vacuum actuators all seem to be working when they should it's just the doors inside are not. I wonder if one is supposed to be connected internally to the other. i did tape one door open and the A/C works great but not right. I am going to Classic Parts (Chevy Duty) in Kansas City next weekend. I hope they have some suggestions. They have a nice store. I will be taking my wife's credit card (birthday) thanks Larry
I was up there once and they had a load of OLD NAVY trucks there--- very cool it feels like Christmas when I get to go.
return to the scene I was at Classic Parts saturday, they had a few nice trucks there, including a 1987 chevy p.u. with 90 original miles on it--- yep 90. it was so totaly stock it still had some of the original window stickers on it also there was a nice blazer and a very tricked silver 52 that almost glowed it was a beauty.... But it seemed like everything i needed was on backorder The counter people were great and they really know there Chevys.
HAHAHAHA I know. sorry If they would just turn me loose in that back room I would build me a new old truck. It's HUGE
I am headed for California next week. I guess I could have brought it for you but they would have looked at me funny carring it onto the plane.
Location of HVAC vacuum switch Does anyone know where this HVAC vacuum switch is located on my 83 C20? AC Delco p/n 15-71518? I have the round vacuum switch attached to the back of the HVAC control in the dash, but I can't find this one.
hello I was looking through this and thought this shot may help, I have more of other areas. I took these to help me remember where my vac lines went. yea its dusty, the lay out of my 77 is very similar to my 87. my 77 has the same valve as the one posted, I believe it is a dealer install factory Harrison A/C system
