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02 Highlander – AC stuck on defogger setting

So to start – I’m… capable, but inexperienced, as it comes to cars? I can understand directions, just don’t know a lot on my own.

Backstory, in case anything is relevant - in my 2002 Highlander, the top cluster of my center console controls (clock, hazard lights, passenger seatbelt warning, cycle air button, A/C button, rear defrost) have not been working for about two and a half weeks. It’s been on my radar, but I hadn’t had time to take it in yet. Drove fine, A/C worked, all of that – mostly just the clock was an inconvenience.

Two weekends ago, my battery died. Took it in, Advance checked it out and topped off the fluids, cleaned corrosion and sent me on my way – said the corrosion might just be shorting it out (it was bad), but that while the battery was old (4.5yrs) it might still be fine, so to try that and come back in 100 miles or so before buying a new battery.

Worked fine that week, died this past Saturday. Went in to get a replacement battery, had it put in, all good. Chugged a little on the first start after the battery was installed, had them check the starter/alternator, they were fine. Started normal after the first time.

Went to leave, and noticed my air conditioning was now coming out of the defrost, instead of the forward setting I left it on. Long story short, now that dial doesn’t work, and I can’t change the airflow direction. (Advance aren’t techs, he had guesses but no ideas for sure – something with the battery resetting the switch to the default).

The temperature control still seems to work – it doesn’t get quite as cold as it did (not sure if that’s a new issue as well, or just how the defrost portion works). I can also still change the strength of the air blowing out – basically, the other two A/C controls work, I just can’t change WHERE it’s blowing out.

My guess was that it would be fuse-related, but I checked all the fuses that I could tell from the manual might have something to do with the A/C (or the center console controls I mentioned), and none looked blown/broken.

I’m not really sure what else to look at – my wife’s dad might be able to help, but he’s busy often, and we’re going out of town on Sunday. Any ideas what I could look for? Appreciate any help.

When you had the battery removed all the many electrically controlled settings in the car reverted to a default mode. On some cars you have to reset your radio presets or the clock, for example. Your AC did that, too. Because the control module is not functioning, you can’t reset it to what you want, so you have to figure out why that piece of the dash is out. I can’t help you there, but if it was my problem I’d check the power cables. Look in YouTube for videos on removing parts of the dash on your Highlander. Things often unclip and pull out and then you can clean the connections and even replace bad parts.

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Look at

It’s a YouTube instruction video. When I brought that up, in the “next up” list was a 3 part thing on repairing it.

Good Luck.

I appreciate the help - we took it apart tonight, and the conclusion was that the climate control module is indeed starting to fail. The air compressor isn’t coming on, and he pointed out a plate that should be moving into place to make it all work that isn’t doing anything.

We’re going to try to look for one at a salvage place, just because of the time constraint – but if it doesn’t work out in time, I might fiddle with looking at the insides like the guy does in the third “how to” video in that chain.

The bright side is, since it’s broken anyway, it’s not like I can make it worse! (Though of course I’d try not to do anything irreparable, if we may be able to still send it somewhere instead of having to buy a brand new one).

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You’re getting there! What you wrote is just what I’ve been doing for years, and that’s how I’ve learned all the stuff I know about cars. Just go ahead, carefully, take pictures as you go if the set-up is complicated, and work carefully. Sometimes things are just broken beyond repair, but sometimes it’s just a minor little thing that’s messing up the whole process.

Report back when you have time.

Updating, just to close things out – I ended up finding a place that I could take it to that would repair the module for $65 flat (knobs and displays only at that price, but still). Dropped it off with them last Friday, and got a call Tuesday that they had tried everything they could and couldn’t get it to turn on. Marked it as an “internal power failure”.

Refunded me since they couldn’t fix anything – I think that marks the end for this one, though. It was coming up on time to replace anyway – but no heat/ac going into winter definitely seals it. Got my eye on a 2013 model – I’ll be sad to see it go, though, it’s been a great car!

Thanks again for your help!

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