AC vacuum switch in center console, diagnostic steps?

[TTait]

I'm going through all the honeydo items on my wifes car and I note that the air no longer comes out of the vents when running AC or heat. The fan works fine. It seems to be the flaps down in the AC/heater box.

The system was working 6 months ago the last time I used the car regularly. No fiddling in the center console area since.

Before I remove the center console to get at the back of the AC console, what should I check thats easy to get to. I'd hate to get the center console out and then realize the fix was elsewhere.

If I crawl under the steering wheel is there any hope of reaching in blind and finding an obvious problem?

I don't hear any hiss or anything.

Is there an easy workaround where I can get the flaps open to route air out of the main vents manually? That's where I want the air coming out 99% of the time anyway.

[WelmoedJ]

I don't hear any hiss or anything.

There doesn't have to be a hissing sound with a "broken" rubber diaphragm in de selector.
The diaphragm has a couple of rubber pins that break off due to age.
Lack of smooth (greased) turning breaks them.

Replacing is not very difficult.

Welmoed.

[sean]

There doesn't have to be a hissing sound with a "broken" rubber diaphragm in de selector.
The diaphragm has a couple of rubber pins that break off due to age.
Lack of smooth (greased) turning breaks them.
Replacing is not very difficult.

+1. I would start with the mode switch diaphragm.

[TTait]

I would like to consider temporarily connecting two of the vacuum hoses together to force the dash vents to open. It would temporarily solve the problem while I ordered the diaphragm, and isolate the problem to the mode switch. I know I have seen a diagram showing which hose is which, anybody have that handy?

[WelmoedJ]

Manual, Page N:08:15
1 = source
2 = lower mode flap = brown
3 = re-circulation & water valve = orange
4 = screen flap = blue
5 = top mode & flv flaps = red

[TTait]

So if I hook the source to the water recirculation hose and the top hose using a small T, thats forcing it into the max AC configuration it sounds like...

[DMCMW Dave]

So if I hook the source to the water recirculation hose and the top hose using a small T, thats forcing it into the max AC configuration it sounds like...

Yes. That will turn off the hot water, pull the recirc door open, and open the center and door vents. If you want the hot water off but still want fresh air, don't pull on the recirc door.


FLV = Face Level Vent

[TTait]

I live in Los Angeles - there is no fresh air.

More to the point I could hard wire the car to run with max AC and only regret it a few days a year.

If that works I'm also 100% sure the problem is the mode switch... If not I have to start tracing out the vacuum supply line - not even sure where that is...

T

[DMCMW Dave]

The supply line is a 1/8" plastic line that runs under the console, it turns into a rubber line about a foot from the mode switch about where the door light diodes are (location varies depending on who's been in there and who built the car!). The back end of the line goes into the left pontoon and ends at the vacuum can inside the pontoon. It is usually visible near the idle ECU.

[TTait]

The supply line is a 1/8" plastic line that runs under the console, it turns into a rubber line about a foot from the mode switch about where the door light diodes are (location varies depending on who's been in there and who built the car!). The back end of the line goes into the left pontoon and ends at the vacuum can inside the pontoon. It is usually visible near the idle ECU.

Aha!

Now - what if I told you I recently replaced the power antenna? I think I know where the problem is.

Are there two vacuum lines in the center console? The one I think I know about is for the heater valve... Perhaps I misunderstand the routing.

Is there a good diagram that outlines all of the vacuum systems in one place?

[DMCMW Dave]

Aha!

Now - what if I told you I recently replaced the power antenna? I think I know where the problem is.

Are there two vacuum lines in the center console? The one I think I know about is for the heater valve... Perhaps I misunderstand the routing.

Is there a good diagram that outlines all of the vacuum systems in one place?

Yes - two lines. One is the heater valve, one is the vacuum source. Come to think of it - the heater valve line is about 1/8". The source line is more like 3/16" diameter. Both are hard black plastic.

There are pictorial diagrams in the service manual and tech manual, but not anything showing specific locations.

This one is about as good as anything, once you know where the parts are.

http://www.delorean.com/store/c-365-7-3-0-electricalmechanical-controls.aspx

19 ande 29 are the two lines you are looking for. If you look closely you can see the transition parts from plastic to rubber.

[TTait]

Aha!

Now - what if I told you I recently replaced the power antenna? I think I know where the problem is.

Yep, the supply line was the problem - back up and running now. Thanks all.

As far as the vacuum diagram, the one Dave pointed out has the AC portions of it, but it would be nice to see all of it in one place, engine, AC, Brake Servo... I know I'm just being lazy...