Auto switch on climate control?

[valkyrie610]

Had the A/C control out this weekend swapping a bulb, and on the back of the thing was a little switch. One end said Auto, and the switch was positioned opposite that.

I can only assume there was some automatic temperature feature that was an option, but Toyota's EPC calls the Auto switch that resides where the factory blank is "heater control #3" or something like that.

Anyone know how this worked & what it controlled?

Any bonus operation by adding the Auto switch and flipping the back switch?

(1996 model)

 

[lumpy70]

On the JDM 80 series, there is an AUTO feature on the climate control which engages the heater, or A/C and adjusts the fan as well.

Not sure how that will help you though, there is a whole whack of sensors to support it.

Sorry,
Craig.

 

[scottm]

My 40th had an auto button in the center blank of the climate control, it was evil. That's probably what the switch is for. I think the CE and Lexus had auto climate control as well.

 

[Atticus]

Had the A/C control out this weekend swapping a bulb, and on the back of the thing was a little switch. One end said Auto, and the switch was positioned opposite that.

I can only assume there was some automatic temperature feature that was an option, but Toyota's EPC calls the Auto switch that resides where the factory blank is "heater control #3" or something like that.

Anyone know how this worked & what it controlled?

Any bonus operation by adding the Auto switch and flipping the back switch?

(1996 model)

It's funny that you should ask. 40th Anniversary, Collector's Editions, and the LX450 all came with this "feature," which controlled the climate control function, but it does not work. At all.

 

[valkyrie610]

My 40th had an auto button in the center blank of the climate control, it was evil. That's probably what the switch is for. I think the CE and Lexus had auto climate control as well.

I know there is an Auto switch to go in that void, My questions are:

How/What exactly did it control that would be different than the sliding temperature control at the bottom?

Is there any value to investigating retrofitting the switch in there?

Evil how?

 

[valkyrie610]

It's funny that you should ask. 40th Anniversary, Collector's Editions, and the LX450 all came with this "feature," which controlled the climate control function, but it does not work. At all.

How did it function?

 

[Atticus]

How did it function?

The temperature "slide" had numbers on it. You put it on a number, and a computer did the rest. In theory.

In reality, it was always either too hot or too cold, so I stopped using it.

 

[bpassmore]

I have the auto option in my LX.

It is evil. I accidently bump it from time to time. I might superglue it in the open position so I dont hit it.

I like the ac controllers with the blue and red lines, not numbers.

 

[NLXTACY]

It's funny that you should ask. 40th Anniversary, Collector's Editions, and the LX450 all came with this "feature," which controlled the climate control function, but it does not work. At all.

I've got a 97 LX and I have the Auto Climate. For me, living in SoCal, it works excellent.

Set it on a temp, click Auto and just leave it. If its a ridiculously hot day then once you start the truck, the hi fan kicks in a few seconds later and helps cool down the truck. And continually slows the fan speed until the cab gets it to the temp you want. Too cold, move it to the right one notch. As you move the slider while in auto you are changing the fan speeds and the air blend. I use it 100% of the time. My wife doesn't like it because on hot days the vent is blowing too hard and makes her hair go all over.

 

[chitown40]

That's all I use (auto switch) unless I need to defrost the windshield. Works great, as long as you consider it was mid-90s technology and not the fancy new computerized gizmos we have in today's new cars.

 

[valkyrie610]

Ahhh, so it had a different slide. Now it makes sense.

I wonder what if any sensor changes/additions were installed to make it work?

Since there is a switch on the back to activate the auto-feature, I would think that it wasn't real different... might already be an existing temperature sensor maybe in the controller or piggybacked in that switch itself? With that on, the auto switch should just work off the temperature slide position (whether numbered or not) and override the fan controls.

My curiosity is piqued... anyone got a picture of the wiring into the two connectors? Short of digging out a FSM, that might be the easiest way to see if there is something additional to retrofit it.

Seems to me that all the pins were in use on both of them, which makes me think the switch is just the key, and the slide is kind of irrelevant whether it has numbers or not... if my line of thinking makes sense.

 

[Ebag333]

It is evil. I accidently bump it from time to time. I might superglue it in the open position so I dont hit it.

Flip the switch in the back from Auto to M. Then it should be completely manual.

I've got a 97 LX and I have the Auto Climate. For me, living in SoCal, it works excellent.

x2, I love it.

I wonder what if any sensor changes/additions were installed to make it work?

It requires quite a bit.

There's a tube that sucks air from the cab to measure inside temp, not sure where it goes (I never bothered to follow it).

There's an outside temp monitor.

There's (I believe) at least 2 computers that control it. I could be wrong and there could only be one.

Long story short, it's going to be a lot of work and *REAL* expensive unless you can find a donor truck. The computer that controls it is hideously expensive (especially if you have an LX).

Maybe you and bpassmore can swap out all the parts?

 

[Chaldaean]

There's a tube that sucks air from the cab to measure inside temp, not sure where it goes (I never bothered to follow it).

I believe the "inside the cab" temperature sensor (thermocouple) is behind the tiny grate on the lower-left corner; just under the "OFF" button if I can picture it correctly.

 

[valkyrie610]

Flip the switch in the back from Auto to M. Then it should be completely manual.




x2, I love it.




It requires quite a bit.

There's a tube that sucks air from the cab to measure inside temp, not sure where it goes (I never bothered to follow it).

There's an outside temp monitor.

There's (I believe) at least 2 computers that control it. I could be wrong and there could only be one.

Long story short, it's going to be a lot of work and *REAL* expensive unless you can find a donor truck. The computer that controls it is hideously expensive (especially if you have an LX).

Maybe you and bpassmore can swap out all the parts?

wow... sounds like a big "f**k it on my idea... even with his parts.

I'm gonna dig out the FSM this week and see what I can figure out... but what sticks in my mind are that all the pins are full. Knowing Toyota's penchant for cheapness (A-Trac hack was the latest I know of) and simplicity of wiring I just keep wondering if there isn't an easy hack.

 

[valkyrie610]

I believe the "inside the cab" temperature sensor (thermocouple) is behind the tiny grate on the lower-left corner; just under the "OFF" button if I can picture it correctly.

Ahhh... my controller has nothing back there.

 

[bpassmore]

here is an auto controller:

 

[valkyrie610]

Cool, thanks for the pic Brett... makes sense for a temp sensor to be down in that corner.

I'm still betting it'd plug into the circuit baord somewhere and hopefully Auto controlling isn't too hard.

Mind if I disassemble your dash someday?

 

[bpassmore]

lol
sure
ill trade ya next time im up in dallas

 

[AdventureBuddies]

I've never understood why people hate the auto feature so much. I use it 100% of the time as well - SoCal climate. I bought the truck in FL and the PO said he hated the auto - maybe it's not so useful in humid climates?

By setting the slider at a certain temp - usually 72 to 75 for me - the system adjusts the fan speed as needed to maintain the desired temp. It also cycles the compressor on and off as needed - not sure if that's an "auto" feature or if they all do that.

 

[MikePL]

OK, I will add my 2 cents.

The additional goodies you need to have to make it work (I may not know all of them).

1. Temp sensor behind grate next to off button. This is a simple thermistor I guess.
2. Outside temp sensor normally located behind bumper below the passenger corner of the radiator (thermistor)
3. Solar sensor. A black nipple located by the windshield above the glovebox.

The auto climate control needs data from these sensors and also from the coolant temp sensor. This is because on cold days the system waits until the car gradually heats up and it gradually increases the temperature. The solar sensor could be omitted and replaced by a resistor which simulates a typical day. You can borrow such a sensor, expose it to moderate sunlight and measure the resistance. Then you buy the proper resistor.

I also know that you probably need all sensors for the system to work. I am sure that you need the in-cab sensor (behind the grate) because my friend had it disconnected in his LX and the blower was getting crazy (blowing always in high, either hot or cold air). You obviously want an in-cab sensor as lack of it defeats the purpose, LOL

The in-cab sensor is on a cable which goes to one of the cable looms attached to the climate control button box. It probably goes straight to the box or maybe somewhere else. It is quite probable that you have it there. It's a black 2-pin connector. Maybe it is taped and foamed to the other cables and can be used.