[MY2J]

So I was driving home yesterday with my windows down and A/C turned off when suddenly I feel a blast of cold air and notice my A/C was "on" (light was lit) even though I had the knob on the "off" position. Then it just started going crazy and turned itself on and off repeatedly. Are these signs of the blower going bad? Fuse? Relay?

 

[jasonm4]

Hey Mike,
Sorry to hear about your console going haywire. So it sounds like the unit powered up fully as if you turned the selector switch on. The blowers variable speed resistor always has power when the car is on but the console controls the resistor and speed signal. I'm wandering if your selector switch contacts are faulty and intermittently turning it on. Nothing but the console can turn the console to an on state. Try tapping on the face plate of the console near the on selector switch, see if it acts up then. There's two contact wipers that may have become dislodged possibly and may be tuning the unit on even if the switch is off. See how the contacts are in a ring, the wiper is on the dials. So try giving it a few taps right on that first selector and see if it turns on. If that's the case you will either need to open it up and check out the wipers or simply get a used unit off eBay for like $50.
http://my.is/forums/f90/how-change-climate-control-center-console-leds-pics-360155/(Borrowed from the DIY threads)

Edit; I did find this thread that is similar but I don't think it's a HTR relay(largest relay behind passenger kick panel fuse box) problem because that only supplies power to the blower whereas your whole unit sounds like it is powering on as if you turned the selector dial from off. There is also a relay for the compressor clutch but again, the console controls that.
http://my.is/forums/f115/c-wont-turn-off-406706/

So give that first dial area or the console a tap and see what happens. Lemme know bro.

 

[IS5043]

I have a similar problem. Usually happens when I first start my car. It would turn o by itself even when the knob is at the off position.

 

[jasonm4]

I have a similar problem. Usually happens when I first start my car. It would turn o by itself even when the knob is at the off position.

Have you tried the suggestions I gave Mike above, as far as tapping that part of the console to see if it tries to turn on/off. My other suggestion was to check the HTR relay behind the passenger kick panel fuse box, it's contacts may be closing on their own. It's either one of the above or the console is faulty. All controls are commanded by the console including on/off.

 

[MY2J]

thanks Jason :approve: I'll give it a few love taps and see if that fixes it

 

[jasonm4]

No problem Mike, I'm just trying to see if it's the dial contacts themselves or not. That is the only thing that turns the unit completely on like how you had mentioned. I'm not buying that a stuck HTR relay would cause the unit to power on, so that info in that link is wrong. HTR only supplies power to the blower controller. I've read quite a number of threads where issues like this and other features would act up and a knock to the side of the unit made it work temporarily, proving that the unit itself was faulty.

Hope that makes alittle more sense...

 

[MY2J]

Jason, took the car out on my lunch break and I tapped the on/off button a few times (harder than normal) and it went away :approve: Hope that's all it was and hopefully it doesn't come back... if not then I'll just grab one off ebay or craigslist. Thanks again brother! I should have done the love tap mod from the beginning :lol:

 

[jasonm4]

A free fix! Well not really. At least we were able to confirm the console or that first dial has an issue. Idk bro, I would think if it keeps acting up then I'd just grab a used one or send it to me and I'll try to fix it lol. Glad you got it at least narrowed down. Anytime Mike!

 

[jasonm4]

Remember you really only need the face plate(or controls). I've seen some used models at like $45 on Craig's list or eBay. Worst case you can swap it rather cheaply but it may be repairable as I believe that main wiper is the issue. Think about it, it's really the only moving parts plus 10 years equals possibility of failure, guess I've been lucky as faulty AC units seem common somewhat. You can always swap it out then fix your existing then flip it for $100 Good luck Mike.

Edit; just throwing this out there. The faceplate is what has the dials, you may be able to just swap it out. Here's one for $30 used.
http://m.ebay.com/itm/271222580608

 

[jamienwurch]

My Lexus is250 2010 heater and air conditioner works sometimes and most the time not, no fan noise but because it works sometimes I'm so confused on what this could be!!?????

 

[01 SolarYellow]

My Lexus is250 2010 heater and air conditioner works sometimes and most the time not, no fan noise but because it works sometimes I'm so confused on what this could be!!?????

Old dead thread 2013. But the issue is the control unit.