DIY Climate Controller Repair -How to

[Jungoes]

So finally after some time I figured this out, and before I begin I KNOW there are users here charging for this service that do not openly share the steps on how to do this.

This really pisses me off because had it not been for the sharing of knowledge on this site I would not be a 4 runner owner.

Anyway If you can install a car stereo or upgrade a brake caliper you CAN do this.

Special thanks to [MENTION=224850]Wishmun[/MENTION] for the pictures as I did not take photos when i did mines and he was kind enough to take the pics when i sent him the instructions.

Anyway the repair is for the following known issues with the HVAC climate controller found on 2000 or newer units.
Common issues:
1. Sticky buttons, erratic display or no control feedback after pressing the buttons.
2. Pressing the centre of the unit and then getting some of the buttons to work.

this write-up will not address any issues with the temp or fan speed control dials due to worn out potentiometers - if you are getting problems with these - change them, you can get them working with some electrical contact cleaner.

Instructions:
1. Remove climate controller from dashboard
2. Disassemble the unit into the two parts- remove outer housing- there are 2 yes 2 boards inside the unit.
3. CAREFULLY disconnect the ribbon cable separating the 2 boards, do not bend or tear these ribbon cables. There is a white clip to move before pulling the ribbons from the sockets.
4. Cut the plastic housing that holds the LCD panel as shown below.
5. Remove the white plastic box to access the solder connections behind the lcd panel.
6.TIP: you can bend the pins from the LCD panel that feeds to the board using a pencil/ pen to allow the rods to bend over a curved surface- ONLY BEND TO ALLOW soldering access.
7. Use a clean soldering iron and gently touch up all the solder connections on the board EXCEPT the Main IC chip that is in the centre. (I only labelled a few spots that are typical on the board)
8. Can't stress it enough- DO NOT LET solder get on the connections on the main chip. ( Ask me how hahah)
9. Re- assemble and enjoy!

This is what worked for me, I don't recommend changing any of the buttons ( mini switches) as I changed mines and that was not the problem.
.
Pictures below and credits to user [MENTION=224850]Wishmun[/MENTION] :

 

[Billy00NC]

Thanks Jungoes & Wishmun!

If the Superbowl wasn't on right now, I'd be tearing down the console to get to my flaky control panel.

I appreciate sharing this information.

I'd also recommend attempting to perform the "DTC Diagnostic Test Mode" as listed in Section DI-578 through DI-582 of the Toyota repair manual before performing this solder fix. There's a fuse that can be pulled to reset the system, plus error codes that point to systems external to the control panel. I haven't tried the DTC test yet, but in my case I don't think the test will run.

If no one else shares the DTC "how to", I'll try to add it here later.

I'll also post whether or not I succeeded.

 

[Jungoes]

Thanks for the reminder [MENTION=128252]Billy00NC[/MENTION]
I did that check before attempting my repair but couldn't get the two switches " AUTO " and R/F to stay on and enter the DTC procedure. The R/F switch is the one that had the short for me to start with.

Pages you referenced are shown below for anyone wanting to try this before

attempting the re-soldering.

 

[4runn34]

Thanks to the both of you for posting this. I'm going to try out the diagnostics procedure tonight. I just bought my 99 Limited 4Runner and the AC worked when I bought it but days later stopped working. Also noticed some of the switches intermittently respond on the HVAC panel. I did a recharge and still nothing. The condenser cycles on and off repeatedly every 10 seconds or so when I have AC turned on and fan on max. Again thanks for the post gentlemen! :thumb:

 

[4runn34]

I finally got around to pulling the Climate Controller out of the dash and took it apart. After looking at it under a mag lens, I don't see any spots where the solder has cracked. Are you just touching up the existing solder points with the iron? Or are you actually adding more solder to each connection of the chip?

 

[Browndirt]

This is great advice. Just brought one back from the dead with this procedure. Whose leg do I gotta hump for a wiring diagram to one of these units.??? Have no power to the 2 small lower background button bulbs

 

[heat]

Finally pulled mine apart and attempted a repair. For a couple of years now I
guess, it's been partially working- temp and blower control, but nothing else.
Fortunately, it's mostly been fine, except when I wanted to direct air through
the dash and not the floor.

So I pulled it apart as described, though I first melted slots in the white cover
to get it past the display wires, then clipped the residue. I spent quite a bit of
time inspecting things and saw no broken or cold solder joints, so I decided
to just reflow the terminals for the wire connector from the back (circled in
red). As of now, it appears to be working fine.

In the time it's not been working, I've also had a mildew smell, which I think
is a function of the system not going through its initial cleaning cycle. Today is
the first time since the ATC went on the fritz that I didn't get the smell.

 

[heat]

And for an update, my repair lasted exactly one day. I haven't bothered again.

 

[Eric Liu]

hello，please help，I want to test my climate control and I dont know how to connect the positive（+） and negative（-），thanks

 

[rare_individuall]

Hey guys, I did the solder trick worked awesome but now temperature control knob is now stuck at one temp, I soldered what I thought where the connection points for that but still no luck. Any suggestions?
Thanks in advance.

 

[96RedRunner]

Hey guys, I did the solder trick worked awesome but now temperature control knob is now stuck at one temp, I soldered what I thought where the connection points for that but still no luck. Any suggestions?
Thanks in advance.

Check for solder bridges between points you soldered. Irons that most people have tips are blunt pointed,
a tapered point think #2 pencil with tip just a touch flat on point.
Can be done using a 4"-6" fine file on iron you have. Luck

 

[turkey_towner]

Big thanks to both @Jungoes & @Wishmun!!!

Wow, big thanks to both [MENTION=67251]Jungoes[/MENTION] & [MENTION=224850]Wishmun[/MENTION] for this fantastic guide! After suffering for years with the stubborn climate control on my 2000 4Runner, I finally got around to solving the problem by following this awesome guide.

My climate control now works like a charm!

Thank you so much for documenting this! :bravo:

 

[Shallom1]

It Worked!! Thank you

I created an account just to say thank you for the guide. I touched up what was easily accessible with my soldering iron making sure not to accidentally connect leads. I cleaned up the board with a little bit of isopropyl alcohol before installing it back into the vehicle. The only downside I had was that I was not careful enough when removing the paneling and some panel pieces ended up breaking and cutting my finger.

 

[Decesaro]

Help

Hello, I'm having a problem with my air conditioner control, and I need a photo or details of the connection between the two boards.

When I disassembled it, the flat connection cable was missing, so I'm going to make a wire-to-wire connection directly by removing the connectors, but for that I would need some photos and angles of the flat cable and the connections on the board.

I'm from Brazil- I decided to correct these defects, I've already redone the central clock and now it's the air conditioning part.

Shared album - Bruno Decesaro - Google Photos
Shared album - Bruno Decesaro - Google Photos


Shared album - Bruno Decesaro - Google Photos