2nd gen Tundra: no or poor heat or AC - heater servo timing and blend door failure

Adding another one to the pile, found my broken piece on the driver side. I have zero heat in the cab, and only a little AC, foot and defrost work, but face not so much. So time for me to find a replacement box.

 

@grayscale where did you find the part.. and where did it go? lol a little bit more in context would be very helpful to everyone.

Thanks

 

Not exactly sure, like I said it was on the driver side, but I don't know the exact location. It fell off when I was pulling the servo assembly out. I got a complete replacement box out of a 2018, I'll add more info once I get back to working on it

 

Alright, so I ended up tearing the whole dash out and completely replacing my box. I found one locally from a salvage yard that came out of a 2018 so hopefully it will last a while. Normally I search local yards on car-part.com but most of those don't know how to list the unit and some I called said they don't even sell them - guess they don't like money. eBay was a bust, way overpriced. I ran across this on Facebook. Not the unit itself, but a yard advertising a Tundra Crewmax for parts. Messaged them and they said $200 for the box and got there as quick as I could. Turned out to be a yard that seems to salvage cabs of vehicles - no rear ends and no engine/front end. When I got there they had me look at it first since the dash was already gone. I took a quick peek and said lets go. I didn't realize till later that I ended up with a box from a double cab. Difference being that there is no servo or function on the passenger side. Didn't notice this when i went to look at it cause all the doors had been removed and there was no interior, nothing that gave away it was a dbl cab at first glance. So being that all sales were final and I had already driven back home 2 hours I figured I'd give it a go. Turns out it works just fine, just no independent temp control for the back seat which I could honestly care less about - that's just where kids and dogs go.

The whole ordeal wasn't that bad really, some tasks under the hood are far worse. I didn't take any pictures of the whole ordeal because the ones blackoutt took are sufficient and once you start into this it would difficult to get a point a of reference for them anyway. I also think a step by step would do more harm than good as taking it all apart on your own helps to build your knowledge of how it all goes back together. I did run into a few sticky spots that I will note for others who come across this in their journey to fix things.

1 - The A-pillar covers and oh shit handles must removed. They hook into the dash and have to come off first. Unclip the wire sockets you find behind them as well.

2 - There is a small wire harness that runs the length of the underside of the top most part of the dash, right up under the lip. It services the dash speakers and a few other bits. The harness extends down to the kick panels on both side where it plugs in to a few sockets on each. These can easily be dismounted and disconnected so the that harness can remain attached to the dash for removal. Not doing this would be a nightmare.

3 - The passenger side airbag that it inside the upper portion of the dash (kind of behind the top glove box) is attached, it comes out with the dash. Just unbolt it from the rail and disconnect it wiring, one socket on each side of it.

4 - When you begin to pull the dash out you will notice something still connected in the far drivers corner. It's a wire from that small harness I mentioned and it runs down behind that far corner. You will be able to look down at it from outside the windshield. It's an airbag wire which makes it particularly annoying since it's one of those two stage clips. First you have to squeeze the yellow connecter and pop it out, and then you have access to unclip the plug itself. Very frustrating but doable.

5 - The bolt that runs from under the wiper cowl to the inside was a little pain cause the wiper linkage is a little in the way. I just used a deep socket and a long extension and jammed my way in. No need to fully remove this just undo it enough so that it disengages the dash support rail.

6 - When I got to the part of pulling the dash rail back away from the box I had to get an extra pair of hands. The harness attached to it is a bit tight but can be loosened a little by disconnecting a few things. The problem is that part of the metal supports are in front of the hvac box while two of them are behind the tabs the support. So you kind of have lift up while pulling back. Same going back in, kind of a pain. You'll see when you get there.

7 - The box itself. At this point the box itself should be completely loose, but when you try to remove it you will find a wire running from the harness on the rail to the back of the box. Your immobilizer is mounted there. That one was a real pain to unclip. I ended up breaking the tabs to get the immobilizer out and decided to mount it elsewhere when I reinstalled everything.

You will need a few odd tools for this as well.
As blackoutt mentioned you will need a T40 torx bit for the dash support bolts on the right that run in from outside the door jamb. TT40 and TP40 will not work.
On that same side are some screw in spacers that you can back out a little to make moving the rail easier but you will a 12mm allen head for this, rather big and not a common size for most people.
You need 10mm, 12mm, and 14mm sockets and wrenches as well as extensions and philips drivers. Flat heads and plastic pry bars are also very handy.

Also remember that you should swap your AC amplifier if you have gotten a box from a different year model than yours, and even if it is the same year make sure to check the pn#s match. I thought about leaving the newer one in to see what happened, but all my searches on different Toyota parts sites said it was not compatible. My old one worked fine anyway so I just stuck with that. May have something to do with digital controls or who knows what.

Lastly, y[COLOR=var(--darkreader-text-000000, #e8e6e3)]ou will also need to swap out that pesky immobilizer. If you do not you will later find that you are unable to start your vehicle or otherwise interact with it. If you did not "break" yours out or are wondering how to remove the donor, pull out the bottom portion first and then the top portion with the tabs. The tabs are useless until the bottom part is popped out.

Now just stuff all that crap back in there. I found that things didn't quite lineup the way they were, and I suspect this is from the dash rail being not in the exact same spot, but everything close enough. Fair warning if you've never done anything like this, dash parts never go back in and fit as well as they did before, you will forever be poking and prodding something or other you don't quite like the fit of. While I had everything out I also took the time to clean as much as I could. The older a vehicle gets the more dust builds up even in the smallest spaces and I figure why blow other peoples skin cells around when I have plenty of my own.[/COLOR]

 

i just replaced my damper servo and luckily only had to take a few pieces off. no center console, either. made things much easier.