98' TL 2.5

I sit in my car on any day in particular, regardless of outside weather conditions.
After inserting the key in the ignition.. I turn to second position...
What am I greeted with?

A fantastic gush of warm air from the HVAC vents!

I did not turn on the A/C prior to shutting down the car. Yet it blows. It angrily blows at me.

It also displays Gibberish on the Climate control screen. It's indiscernible.

While this fantastic display is occurring, the system will seem to flicker between "normal-mode"(display is normal with A/C off) and "demonic-mode" (where it blows the fantastic hot air at my face while displaying gibberish!)

I recently had a flex pipe welded onto my exhaust system that fixed a leak... the car runs much quieter... related?

Any ideas before I start taking the dash apart to see if there are tiny unicorns jumping around my blower motor?

 

bump... someone's got to have an idea...

 

did you do a/c recharge? so you can blow cold air

did you do the trouble shooting on your climate controls? if not there is a service manual ,shows you how.

 

It's not the air that bothers me so much. It's the fact that it's turning on by itself... as if it had it's own willful rebellion to blow on and off whenever it feels like it... but thanks... I'll troubleshoot through it and come back if I have any questions....

 

Except... none of the pages on my FSM downloaded from the forums link properly... it's a nightmare -_O

 

so first off I would like to thank 2012 for trying to bring the dead 2008 back to life. second I am have the same problem as the OP, I replaced the head unit and it worked for about two weeks and now its gone to crap again. I am only hoping you guys are still linked to this thread.

 

I would like to also add that when I take the unit apart there seems to be a burn mark in the front right corner of the screen of the climate control unit after it goes nuts.

 

So after much much work I have solved the issue. I researched all the components of the a/c system and the only thing that made since was the blower motor transistor. As a transistor puts out higher voltage then it takes in, shorted it feeds excess power back into the head unit destroying it. Also as I removed the blower transistor tons of leaves and debriss fell out of the blower housing. As the transistor is about $75 used I decided to break out the soldering iron and replace the faulty components. Taking the unit apart was easy as a couple of screws and heating the old solder joints while lightly pulling on the transistor. Note there is also a thermal resistor to replace under the transistor. I refreranced the part number and was able to get a replacement transistor for $15 shipped. Now i already had a new A/C head unit waiting to go in when the problem was identified (ebay $31). The worst part of this job was removing the dash to clean out the debris from the blower housing. I hope this helps someone one day in their pursuit of repair.

 

I have the same leaf issue, but my blower motor is bad, thanks for the info on fixing the blower resister. I'm going to try that before I buy a blower motor just to make sure it's not the resister, I very good source told me that the transister can test good even when it is bad so I will repace it just like you did. I will let you know how it goes.

Thanks again.