Thanks for the write up

 

Hey that's fantastic! For the benefit of other TN DIY's, could you describe the steps (and tools) needed to get at the circuit board, and then puttting it back together. Thanks - Hammer

 

Sorry, I forgot to mention that...
The tools that are required to do this:
A normal size flathead screwdriver
A miniature flathead screwdriver
A normal #2 Phillips screwdriver
A size 10 socket with extension
A ratchet
Soldering iron
Solder
Small gauge wire, I used strands from CAT5 wire.

The cover on the dash over the climate controls and radio pops out, I used a plastic window tool, but a screwdriver will do just fine.

After the cover is off, there are 6 10mm bolts holding the radio and climate controls in.
With the 6 bolts gone the control panel comes out in one piece. be sure to unclip the wire connectors.
The radio has 4-6 screws on the side holding it in.
On the back of the climate control there's a plastic cover that has 6 screws holding it in, use Phillips screwdriver, there's The main plug connecting the plastic cover board to the main board, so don't yank the plastic cover off when unscrewed.
Carefully undo the wire connector and set aside the cover.
Now you can see the control board.
The board has 4 screws to hold it to the front cover, take these out it's easier to solder with the board out.
The control knobs each have a screw holding them in place.
With the boards out, you can desolder the ribbon wires and cut your new wires and solder them in and put it all back together.

 

added to the stickies :thumbsup: thanks!

 

this is for the limited right?
the base model manual heat control has the same problem. Don't understand why, poor quality control

 

Yes, this is for the limited model, but I know the base models are similar to it.
I'm really not sure why they have poor quality on this stuff, crazy things happen, but at least the highlander hasn't ran through a wall yet. Haha

 

Thanks for the post. I actually found the following last year:
http://www.devalcourt.com/2010/03/fixing-2004-toyota-highlander-ac-and-heat-issue/

The poster in the link I provided seems to think that the problem is that the ribbon cable is short and under stress, making it susceptible to breaking. My two year old pulled outward on the temperature control knob and that seems to be what broke it.

I was looking for some 3-wire ribbon cable, but separate wires might work as well. Do you know what the original wire gauge is?

 

Do you know what the original wire gauge is?

That's a low amperage (or should be put low mA circuit) circuit, just about any gauge wire should be fine. Someone above said they used CAT5 wire, and those are tiny. So anything you get should work :thumbsup:

 

The original wire size were a 28 gauge. The CAT5 wires I used are a 26 gauge wire.
Be sure to cut the new wires longer than the original wires were, otherwise you might have the same problem happen later on down the road.

 

I ended up going to a hobby store to find small enough wire when I fixed our 2005 Base HL. Also, be sure to desolder the board before adding more since where the wires attached are very close together. Solder wick worked great.

 

I know how to solder but never have done small things like this, how hard is it and is there any difference?

 

Just be sure to use electronics solder and an iron designed for electronics. Acid core solder and iron for plumbing with destroy electronics.

Its super easy just practice soldering a few scrap few wires together or onto a scrap board beforehand to get the hang of it. Be mindful not to overheat the baord or nearby components. Also getting a desolder pen or a solder wick to pick up/remove melted solder is helpful.

 

Climate control knob repair

This looks like the repair I'll need, but do you have instructions for removing the console? The posts I've seen elsewhere are for a different version of the 2006 Highlander. Mine's like yours. Mine is 2006 Toyota Highlander Hybrid (Canadian market)

 

Hello. I plan on trying this fix to my 2002 Highlander.

This site is so helpful.

I found these 6” no-solder 26 gauge jumper wires at an electronics store. Seemed real convenient lengthwise.

Can they be soldered into the boards just like a cut-then-stripped wire?

 

That looks like a probe crimped onto the end? I would think if it is you would need to clip it off and strip out some fresh wire.

 

Thanks a lot. Wondered about those ends.

 

Actually, having done this repair several times, on several different control units, I've formed the opinion that it is actually the soldered length of wire that is causing the problem, along with the associated knobs loosening over time. What I HAVE found to work, long term, is to crimp female Dupont terminals to both ends of a length of wire, and solder 2.54mm (on center) pin headers into the locations where the wires were formerly soldered--on both the controller PC board, AND the knob PC boards. At that point, you have a controller PC board with a bunch of pin headers to be connected to knob PC boards with pin headers on them, and interconnect jumper wire sets connecting them all together.

Since doing this, a number of years ago, I haven't had a single recurrence of the issue.....and I HATE having to fix things twice.

 

As a follow-up clarification to the above, this is what I'm talking about:

This is the mode switch connection point on the AC Control Unit PC board. A six-position, right-angle pin header is installed, with an identical pin header connection point on the PC board that the mode switch is installed on.

After the same fashion, the Temp Switch connections are addressed with right angle pin headers installed on both the controller PC board and the PC board upon which the temp switch is installed.

As noted in this photo, if you are, as I have mentioned elsewhere, replacing the OEM clock with a clock module sourced from elsewhere, the indicated traces on the controller PC board are best cut.

Because the front passenger-side occupancy telltale is connected to the PC board in the same manner as the mode and temp switches, I treated it to the same remedy.

Likewise with the Emergency Flasher switch and switch illumination lamp--the incandescent lamp should really be replaced with an LED or LED array.

In total, there are 5 incandescent lamps in the AC Control Unit housing for the following purposes:
One lamp for clock back light illumination.
One lamp for Emergency Flasher switch illumination when the parking lights / headlights are enabled.
One lamp for the front passenger occupancy telltale flashing indicator.
Two lamps for the AC Control Unit control knobs and settings back light illumination when the parking lights / headlights are enabled.

If you tore this thing out, and apart, you really don't want to have to do it again. I highly recommend replacing all incandescent lamps with LEDs or LED arrays.

 

Well, I did this repair and my temperature control works!!

I was nervouse to try this (but the part was already broken, so what the hell).

This forum and the greater web is so fantastic. Lots of info, did the repair while watching a Youtube video.

I'm not a mechanic, but I was still able to do this, and saved myself lots of $$.

Plus nobody can see how crappy the soldering was, with it all closed up.

Thanks Toyotanation!