It's time for me to practise what I've been preaching. Today I started troubleshooting the ATC (Automatic Temperature Control) in the NYB. I've never actually ever repaired a non-functional unit before so this is a first for me. I moved the car outside to get more light and so I could run the engine without sucking exhaust. This is basically what I found:

The Hot/Cold air door is stuck, well, it was. This was no doubt more moisture damage. I was able to free it somewhat but not enough. The servo itself moves this air door by way of a lever on top of the air box.

I am considering cutting an access door in the front of the air box to help me free this door.

The "amplifier" was bad. I replaced it and things worked better so I guess that means it was bad. The amplifier is the little black box mounted to the extreme right end of the air box.

At least now I know what I am up against with the ATC. It was one of those big question marks all along. I think I got away lucky actually.

The pictures on this page were taken of my ATC model that I put together a few months ago to teach myself about the system. I learned alot about it and it was invaluable in diagnosing my 76 NYB's ATC.

Today I set to removing the blower motor/fan assembly. This is unnecessarily difficult. This kind of thing makes me wonder what Chrysler engineers were thinking when they designed these cars. They certainly weren't thinking that anyone would ever have to SERVICE the car or anything!

First, I removed the plate that covers the blower motor and holds the hood's torsion bar slider. I had to support the hood with a prop on the other side to hold it up.

Two of the three nuts that hold the motor in are accessable without removing anything further. You need to drop the inner fender to get to the third nut.

I had to drop the power antenna down and give it a turn to attempt to get enough clearance to remove the blower assembly. There is a brace under the fender that needs to be removed also in order to remove the blower motor.

I was able to rotate the power antenna enough that I could pull it clear out the bottom. That still did not give enough space to install the new blower. I then had to remove the fender support brace from inside the fender. There are two bolts that hold it to the panel up top and two more that hold it to the firewall at the bottom. Once I remove that brace, there was more than enough space to install the new blower.

With the power antenna and the fender brace out of the way there was more than enough space to remove the old blower.

Install the new blower.

Reinstall the fender brace.

Reinstall the power antenna.

Bolt the inner fender back into place.

Even though I pretty much had the ATC repaired enough to pass safety, there was one nagging issue. There never seemed to be enough vacuum present at the Master Switch to turn the system on. I had planned to bypass this because the only effect seemed to be that the blower would never turn off but would rather stay on low when you shut off the system. Well, I got playing with it again tonight and I noticed the little valve that is mounted near the Fresh Air/Recirulated Air mode door. This is on the extreme right end of the ATC unit.

I noticed that the valve plunger wasn't springing up the way it should. Fortunately, I had two spares :-) I simply changed the valve and the ATC now works perfectly! The refrigerant is low so there is no cooling but that was expected.