1969 Picture Needed

Paul Steinberg

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I need identification help from someone that has a 1969 Cadillac with factory air conditioning.

Request 1:
I have one vacuum line on my 1969 Cadillac, that I have no idea where it is supposed to go to. I need a couple of pictures of the firewall, under the hood of the car, along with a description of where this one vacuum hose goes to.

Request 2:
At the front of the engine, there is a thermal vacuum switch. If possible, I need to know what vacuum hoses are connected where on the switch, and where do they go to. I know that one vacuum line goes to the vacuum connection at the bottom of the carburetor, but I don't know to which terminal on the switch the other end of this hose attaches. Another goes to the distributor, but where does it go on the switch? The third one goes to the heater / air conditioner control, but which is the terminal that it goes onto? I have no idea what the 4th one is for. I had thought that 3 might be identified by the letters on the switch, however, this is one of those times you need to be certain. I am thinking that the M stands for manifold, and the D for distributor, C for carburetor, and that would leave the last one for the heater / air conditioner. Problem with this thinking, is that there are a number of vacuum lines on the carburetor, and there is no vacuum take off on the manifold for 1969.

In picture 1, you can see the thermal vacuum switch is located between the distributor and the power steering pump.
In picture 2, you can see the mystery vacuum line sticking up. This line has a yellow tracer paint line on it for identification purposes from the factory. Unfortunately, the factory vacuum diagrams are not available in the service manual.
Picture 3, is a overall shot of the firewall so you will know where to look. If you can't determine where any of these lines go, possibly multiple close up pictures will allow me to follow it like a detective with a magnifying glass. You can post up to 8 pictures to each reply, and the more detail the better. I have been struggling with trying to get my heater / air conditioner working, and without locating where this vacuum hose goes, all is lost.
Thanks Paul
 

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I’ll try

Here is a diagram I found online. I will go out and see what is on our 69.
 

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I know mines a 68 so there will be slight differences but I can check mine today as well. I know I already have a picture I took awhile back of that area, also yellow, but I cant really tell. I'm missing a different hose. From my picture i cant tell whether the yellow spot is missing a hose and the hole is yellow, or if theres a yellow hose coming out. I will check, getting off work early today.

I dont think my loose hose goes to your port, because looks like that hose is going somewhere else for you, but I will check this afternoon if Rich doesnt first
 

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Found one answer so far.

Paul, our car is tucked away. I was able to determine that your mystery hose goes to the port on the switch that is the highest in your photo. If I get a chance this weekend I will take a better look.
 
Here is a diagram I found online. I will go out and see what is on our 69.

I also found that picture or diagram when I did a Google search, but immediately discounted it as being mislabeled as a 1969, since the 1969 doesn't have a EGR valve, throttle body, map sensor, vapor canister, vacuum pump, and the list can go on from there. One has to be careful when doing a Google search, since the information is only as the person who posted it. The same goes for youtube dot com. I have seen so many videos that give some very bad and dangerous information, such as using never seize on the keyed axle shaft on the 1950's cars that use the axle nut to retain the brake drum. The manufacturers specifically specified as much as 600 foot pounds of torque on that nut, to make sure that the brake drum hub was secured tightly to the axle. It depends on that friction fit for safety, and never-seize is designed to prevent friction adhesion. This is why a large and expensive tool is required to removing these brake drums.
Thanks for trying, and I patiently await your pictures this weekend.
 
I know mines a 68 so there will be slight differences but I can check mine today as well. I know I already have a picture I took awhile back of that area, also yellow, but I cant really tell. I'm missing a different hose. From my picture i cant tell whether the yellow spot is missing a hose and the hole is yellow, or if theres a yellow hose coming out. I will check, getting off work early today.

I dont think my loose hose goes to your port, because looks like that hose is going somewhere else for you, but I will check this afternoon if Rich doesnt first

What you are holding in your hand, is the left side windshield washer nozzle. Like so many of them, the soldered connection to the bracket that is mounted on the underside of the hood has broken free. The white plastic part on your windshield wiper motor is the windshield washer pump. There are 3 ports on that pump, one is from the windshield washer reservoir, and the other two go to the squitter's mounted under the hood edge at the windshield. If you can hear the wiper motor clicking when you push the button, then the pump (white plastic part) is worn out, and needs to be replaced. They are inexpensive, and easy to replace. Only 4 small screws.
The large metal "soup can" mounted vertically, is the vacuum reservoir, and it should have 2 ports on it. One goes to engine vacuum, and the other goes to your heater / air conditioning control. In some instances, there might also be a tee in the line for another vacuum operated items, such as a vacuum operated trunk release. That vacuum line, I believe is split under the dash to go to both the neutral safety/horn/parking brake switch. This switch is mounted at the base of the steering column, and as a multi purpose switch, it controls the vacuum release of the parking brake when you shift out of park, and prohibits you from starting the car in anything other than Park and Neutral. It is also the contact for the horn so your horn will blow no matter how much the steering wheel is turned. At the underside of the switch is a spring mounted contact that rides on a copper disk that is attached to the steering shaft to complete the electrical connection to the horn relay.
 
Good to know, thanks. Always wondered what that was. Not sure how helpful it will be but I will still check that yellow hose when I get home
 
As i recall 68, is the older style ac set up 69 was the change over year and 70 the the changed year. So 69 has things on it that the others don't have. The vacuum thermal port advances the timing at idle with the AC on. As i remember it one line went from it to the neutral safety switch. So that in park it got vacuum . The safety switch is 69 only also. The purge valve out side fire wall and the check valve inside fire wall are hooked to it also. I never did understand why the wanted to dump vacuum. But there was the temperature flapper out side you could see work as it let off the vacuum.that line inside would go either on the controls or the safety switch. Most likely with a t in another line. I'll look over the pictures I have here to see if there is any help.
 
I'm seeing the black with yellow trace coming out of the controls and threw the fire wall to the temperature control valve. then of course it which black with yellow tracer.
 

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Here ya go

Ok, we know your mystery hose goes on the top port in your photo. Using the same photo (ours is in the first photo{upside down}), the left port goes to under the distributor (2nd photo {right of #1}), middle port goes to driver side front of carburetor (photo 3 {below #1}), right port goes to a T that goes to passenger side front of carburetor (photo 4) and to something next to the alternator (photo 5). I hope this helps. NOTE: Some of the photos are rotated due to using my phone to take photos.
 

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Edit

I went in and rotated the first picture of our switch but time expired before I could save the change. Disregard the “upside down” reference. So I guess to clarify: photo 2 goes to the D port, photo 3 to C port, and M goes to the t in photo 4 which splits and goes to carburetor and the part in photo 5
 
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