Thread: Toyota Corolla E12 HVAC LCD

What's an HVAC?

Heating, Ventilation, Air Conditioner or climate control

I'd usually say it'd definately be really hard, but... that many pins.. it's POSSIBLE that each correlates to something being just set on or off. If it was a character display w/ something like an HD44780 chipset or something, it'd be super tough, but it might be worth hooking a multimeter up to the pins one at a time while it's hooked up and monitoring the voltage as you move the controls around. If all it's doing is completing a circuit to activate the bars on the graph and the individual digit blocks for the numerals, then you should be able to monitor it via parallel port pretty easily. If it's communicating with it through protocol, though...

Question, can you get us a close picture of the BACK of the LCD? Tell us, does it have an IC chip on it? Or do each of the pins go straight to the display itself?

Here is a pic of the back of the board!!
Unfortunately every pin comes from that chip!!

So I suppose it is very hard-impossible???

Would there be a problem extending the lcd's pins??

Wow, looks hard. Hmm... what about CAN BUS? What year is your car? I wonder if the new Toyotas support CAN, and if so, whether or not this data is available on it. If so, you could get access to it and more through a simpler interface.

If not, it might be worthwhile to play with the pins of the LCD like you said, but be careful. Figure out what sort of voltage it's using (probably 5v or less) and play with it.

I don't think about CAN, I haven't heard anything.. It is a 2001 model...
Although in the Car's electronic diagram it mentioned something about CAN...

What does that chip say on it...

188071-2100
-a 0101 R2
Uho 1ja1g

How did you interface your HVAC and to what? Your HVAC has it's own LCD or are you talking about the clock LCD?

I've got an 04 Corolla S, I don't have an HVAC LCD, just the clock LCD which I've replaced all ready...

Thanks for the info!