Auto to Manual Temperature Control - 89 GMQ

[5.0turbines]

Ok, so I remember reading somewhere on here that you could easily convert to manual temperature control if you got the cable from a non ATC car. So as of now I have the dash down in my 89 GM w/ ATC and I found out something interesting. I don't know if anyone else knows this, but I took the cable that connects from behind the slide lever on the temp controls on the dash that runs up and connects to the ATC sensor, then I removed the blend door vacuum motor and stretched the cable over to the blend door lever and it reaches! So now all I would need to do is punch the box with a screw or fab up some kind of bracket and I'll have manual temperature control. Yay! Pics.



Heater evaporator blend door vacuum motor. Here you can see the black antenna cable.


ATC sensor and cable.



Blend door lever.


ATC sensor cable removed.





From here you can pull the cable from over the vent tubes and under the dash and route it the the blend door lever.


Here are two of the white blend doors. I believe these are for the floor and the defrost vents. idk. I manage to break one by accident and the other was already broken.




And here's the back of the dash with the vents removed.


And here's what I believe to be the plenum area and 3 vacuum motors for the doors.

So in addition to everything I just posted I have questions, if I were to bypass the ATC what would I need to do? Because if I just left it hanging wouldn't that create vacuum leaks?

[gadget73]

Seal off the vacuum lines to it, and you should be fine.

The busted plastic air door hinges can be replaced with small steel hinges if you do a little tweaking on them. Once you do that, its pretty well guaranteed to never break again.

[87gtVIC]

Good job mang. I wanna see your mounting solution.

[85crownHPP]

my hero!!!
Does it look like you could do this without removing the whole dash?

[5.0turbines]

Seal off the vacuum lines to it, and you should be fine.

The busted plastic air door hinges can be replaced with small steel hinges if you do a little tweaking on them. Once you do that, its pretty well guaranteed to never break again.

I wish I had seen this post sooner, would've given me a little more hope. Yeah I just tried to do that with some small hinges and I ended up drilling holes everywhere. The damn hinge wouldn't line up and it's hard to use a drill then I got really angry and ended up chopping the small pins out with a pair of pliers and removing the two doors. I don't think it'll mess my air up though because the way I studied it was that I'll have air out of the panel and floor same time always, and with the defrost on, air out of the defrost vents and panel always. Btw, do you know if the whole heater core housing will come apart because it looks riveted and sealed? I don't want to screw anything up.

Good job mang. I wanna see your mounting solution.

I'll get creative somehow with my bag of screws. I don't trust the ATC from what I read here and I don't want to spend money on a near obsolete part, plus I love free upgrades even though the heater or AC don't work. lol.

my hero!!!
Does it look like you could do this without removing the whole dash?

I think you'll at least need room enough to remove the cable and screw from the ATC sensor, remove the radio and grab the cable because it's snaked under the dash sandwiched in between the vents and the upper metal part of the dash, then some to get the blend door vacuum motor off which easily accesable with the glove compartment down, couple of screws. Then a little more room to see everything and set it up. So yeah idk really, you may end up taking it down. I was actually cleaning out the interior and I had the carpet and seats removed waiting to dry so I searched some post on how to remove that light switch knob and everything was a go from there. Then after that I went for the heater core. Besides I love to present my self with challenges so I know what's to come ahead like maybe a bad heater core or something. Plus I love this car.

[gadget73]

Drill the rivets out and the halves come apart. Use small screws to put it back together. I think a #10-32 x 3/4" machine screw with matching flat washers and nuts will do nicely.

I actually removed the part of plastic hinge that remained riveted to the inside of the box. I kept the flat part that actually sits against the side of the air plenum, and cut off the angled piece that formed the hinge. If you're looking at the part in question, you'll see what I mean. I used the flat pieces under the hinges as spacers to get things lined up better. Its not totally perfect, but it works a hell of a lot better than it did with broken air doors. You really don't want to run it wide open, you won't have defrost worth a crap.

[pstrbrc]

my hero!!!
Does it look like you could do this without removing the whole dash?

Ummmm..... Only if you've got double-jointed Auschwitz arms, and one of those funky cameras that the guys on TV use to look through tiny holes in ventilation systems so they know where the bad guys are.
I've ripped out all the vacuum controls and will have it set up with 5 push-pull cables. I used manual choke cables. It's nowhere near done, and I have to pretty it up. The wiring for the fan switch also goes through the vacuum switch system as well, so I'm still playing with that. But I' also putting a full set of gauges under the existing plexiglass cover, so the dash will be apart several more times. BTW, anybody know how many different size sheetmetal screws Ford used on these dashboards? I think I counted 6 different sizes when I took mine apart. With 4 different hex head sizes, as well as the occasional obligatory philips head. Replaced every one of them with #8x5/8 screws with 1/4" hex heads. Boy, does THAT make it easier to take apart and put back together! Especially when I found some of the philips heads right up against the windshield, going straight up and down!

[5.0turbines]

Heater Box Blend Doors Round Two

Drill the rivets out and the halves come apart. Use small screws to put it back together. I think a #10-32 x 3/4" machine screw with matching flat washers and nuts will do nicely.

I actually removed the part of plastic hinge that remained riveted to the inside of the box. I kept the flat part that actually sits against the side of the air plenum, and cut off the angled piece that formed the hinge. If you're looking at the part in question, you'll see what I mean. I used the flat pieces under the hinges as spacers to get things lined up better. Its not totally perfect, but it works a hell of a lot better than it did with broken air doors. You really don't want to run it wide open, you won't have defrost worth a crap.

Yeah I see what you mean about the rivets and using the old plastic hinges as spacers, but I did away with them. I ended up using sheet metal screws all around. For the bottom door I bent the hinge so it lines up right. The bottom door is 99% perfect open and closing but the small top door sticks open and doesn't pull all the way back (not by much). I also ended up cutting the lower part of the upper door, because I thought the doors were hitting, trying to find out why it didn't fully open (as in blocking the defrost and floor vents) and I learned that the hinge has to be set up right for the vacuum motor lever to push full in and full out as it needs to. Mine was bottoming out when blocking the defrost and floor vents so the door didn't seat all the way. On my next visit to the u pull I'll grab another box, I can live with this.

[5.0turbines]

Blend Door Hinges

[5.0turbines]

Done!

Here's the mount setup. A strip of sheet metal and and some self tapping screws. Very simple.


Full cold.


Full hot.


By the time I grabbed all of the ATC equipment off I was left with these two hoses. To plug them I took a spring from a clothespin and straightened it out with some pliers. They plug the hoses well.


GTFO

[87gtVIC]

:cry: I cant see

[5.0turbines]

Fixed. yeah, sorry I moved the pics around and lost the links.

[87gtVIC]

Nice job mang. I like the spring too. Today changing my heater core I found a golf tee plugging a vacuum line I had lol

[gadget73]

Dip the springs in RTV and re-insert them so you have a more positive seal.

[5.0turbines]

Update

Alright, so I got my dash back up yesterday. Only took from about early to late afternoon to get it all back together. I had to wait so long because I didn't get a new speedometer cable to replace the busted one until last weekend and since then I've given the entire interior a "sweep".

Today I let the car run and get hot. Whenever I move the temperature slide over to hot I can feel the heat come on now (80 degrees outside). Didn't do that before or either I didn't notice because the heater core was bypassed just before last winter and it was recently replaced. I don't have working a/c but whenever I move the slide back over to cool the air isn't so hot anymore. So now I know everything is working well except one thing.

The blend door setup is INOPERABLE. I learned those two doors I half repaired controls the panel air and since they're halfway stuck open all of the air goes straight to floor. I have no air from them. NONE. The old box is ruined and now a new heater box is on my list of things to get.