atc purple line-vac diverter valve turquoise line-thermal blower lockout switch

[jaywish]

Well I finally got into the atc vac leak. I found two hoses off the connector at he rea of the atc that do not hold vac. The purple one and the turquoise one. The purple supposedly goes to the Vaccum diverter valve and the turquoise to the thermal blower lockout switch.

Since the purple had the bigger leak I tried to find that one first. I followed the line up into the dash behind the glove box and it disappears behind the big gold can which is I believe the servo motor. I will likely take out the servo motor next to see if that helps me trace the destination of the purple hose. I have not been able to figure out where the Vac diverter is by using the Electrical & Vacuum manual. It states Behind RH side of I/P near heater plenum chamber...no figure available". Anybody know how to get to that?


I have not even tried to find the route of the aquamarine hose which I believe goes to the thermal blower lockout switch. I found a component location picture on page 50 figure 2 of the manual. If I am looking at it correctly, which I hope I am not, The thermal blower lockout switch is under the intake manifold. ????

Am I on the right track for these hoses? Any guidance would be appeeciated.

Jay

[gadget73]

The diverter valve is actually easy to get to if its the one I think you mean. Pull the cardboard stuff out from under the dash and its right there. Should be the low mounted can that works the door that you can see clearly from right above where your feet go.

and yes the TBL is under the hood in the heater hose. It should not be under the intake manifold but hanging somewhere in the middle of the valve cover. Usually the easiest fix for that thing is to delete it.

Interestingly, the plumbing from the TBL connects to the diverter, so that actually may be the entirety of your problem.

[jaywish]

The thermal blower lockout switch is the heat mode thermostat with vac and electrical controls mounted alongside of the ex manifold in the heater hose?

The can low on the far right wth the lever sticking out the front is the "outside recirculate door vacuum motor." Is that the one you think might be the diverter valve?

Jay

[gadget73]

Oh, the diverter valve is something else then? I was under the impression Ford called the fresh/recirc thing the diverter valve. Well what the hell does it divert then? The only other vacuum motor over on the right side is the temperature control actuator itself, but that runs through the ATC sensor above the glovebox. All the rest of the vacuum motors are basically behind the radio area. Should be 3 behind there if memory serves.

Yes, the TBL is the vacuum/electrical dingle in the heater hose on the passenger side. I just remove those entirely after having one blow up and overheat the motor, and extensive trouble with them leaking and causing problems with the controls. Seal the vacuum lines off, jump the electrical connection together, use a connector in the hose, and install the TBL in the trash can.

[jaywish]

Exactly my quandry. The hose seems to lead up into the dash, can not see anything with the steel top plate in the way.

The only reference I see in the vac/elec manual is under the Panel a/c section. "With in-car temperature well above the Temperature Control Setting, the modulated vacuum at the servo motor is high. The vacuum diverter valve moves to cool position, and the Outside Recirculate Door lets inside air recirculate.

So from reading tonight I did learn that the panel position starts out in what is conventionally known as Max a/c (recirculated air). It automatically shifts out of max to normal outside air when the car is almost cooled down. Panel is the only position that offers recirc air for quick cool down.

[jaywish]

Exactly my quandry. The purple hose seems to lead up into the dash, can not see anything with the steel top plate in the way.

The only reference I see in the vac/elec manual is under the Panel a/c section. "With in-car temperature well above the Temperature Control Setting, the modulated vacuum at the servo motor is high. The vacuum diverter valve moves to cool position, and the Outside Recirculate Door lets inside air recirculate."

So from reading tonight I did learn that the panel position starts out in what is conventionally known as Max a/c (recirculated air). It automatically shifts out of max to normal outside air when the car is almost cooled down. Panel is the only position that offers recirc air for quick cool down.

[jaywish]

Well I learned a bit more. Did not solve my problem but I guess I am getting closer as I rule out things. The diverter valve mounts on and at the rear of the servo motor. I no longer think the purple line had a leak as I think it connects through the diverter to the black vac line which branches back to the vac tree. I do not know if the diverter valve should function in this manner. Anyone?

I did find and fix a leak in the turquoise line near the thermal blower lockout switch.

I thought I had it beat but no. No change in operation. At idle everything is fine. Open the throttle while driveing and the system drops out and switches to the default, defrost. Close throttle and it takes a while to return to regular proper operation. If you raise the idle in neutral the system does not drop out.

So far found and fixed;
the line to the soup can
turquise line to tbl
leaking egr
3 way valve coming out of air pump

I did not check the tbl for internal leaks yet and I will have to check the atc system as a whole for leaks at the black line comming off the vac tree and heading into the firewall. I thought I got them all but maybe not.

Any other recommendations?

Jay

[gadget73]

is the check valve at the firewall good? Thats where the soup can and the line into the dash connect. If its not working, the soup can basically does nothing and the whole system goes bonkers. The TBL also usually leaks internally. Thats a big part of why I get rid of them.

[jaywish]

This one is 12 months old but it will be the next thing I check. Also did check valve off tree but I was thinking of rechecking it.

[jaywish]

the Check valve was bad but it did not solve the problem. I have at least one more leak. The soup can line is good and hold vacuum, so it is somewhere after the check valve and going inside the car. It is leaking a bit less then it was originally but I can not pump the vac above 5" with the hand pump and it drops down to zero semi slowly when I stop pumping.

Back at it again.

[jaywish]

Well I figured out one thing that was giving me fits. I have been using a set of surgical clips or clamps? to pinch off the various lines for testing. It turns out they do not always fully seal the line. You can see why this makes diagnosis difficult. It is a good thing I can laugh at myself.

[sly]

don't forget to check the soup can. see if it'll hold vacuum. if it's got a rust hole in it, it'll leak and you may not be able to find the hole.

[jaywish]

Soup can is good. The 2 part epoxy has held up well for a few years now.

[miamibob]

Is the "soup can" for cruise control? If not what is it's purpose??

[jaywish]

It is to provide vac for the atc when engine vac is low.