A/C on-off knob questions

[glennm01]

I climbed into my FG's cab recently to find the air conditioner on/off knob laying on the middle seat. Weird. After further investigation, I noticed that there are three little springs in the base of the knob, so my working theory is that whatever secures the knob in its hole in the dash must've failed, thereby unleashing the spring pressure and launching the knob onto the middle seat.

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Those are the pieces above, and here's a shot showing how they all fit together:

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If I try to put the above back into the hole in the dash, gravity being what it is, everything just falls out of place before I can get the knob seated, leading me to believe I'm missing something that holds all of this together. I'm also not clear on what holds the knob down in its dash hole (i.e. so you can't just simply pull the knob out). Does anyone know how this is supposed to work? I can't imagine any of these parts are still available (this is from an '04), but say the word if you know otherwise. I'm guessing I'll have to hack together a custom fix, but it would be helpful to know how the original worked.

 

[SkiFreak]

Is this one similar to what you are looking for?

Air Conditioning AC Switch Heater Control Knob For Mitsubishi Pajero Montero MK2 | eBay

Find many great new & used options and get the best deals for Air Conditioning AC Switch Heater Control Knob For Mitsubishi Pajero Montero MK2 at the best online prices at eBay! Free shipping for many products!

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[glennm01]

Wow, that looks encouragingly similar from the outside, but I don't think it will work. On mine, the round plate with the bumps actually rotates when the knob is turned, thereby completing the circuit in the dash. That Montero knob has spade connectors instead, which I assume means it must be fixed in place once plugged in, so the actual switch mechanism must be inside the knob itself.

 

[kerry]

I just bought a new one for mine and pushed it it after it failed. Pretty simple replacement

 

[glennm01]

Wow, excellent. Did you order it from a dealer, or did you find it somewhere online? If the latter, do you have a link?

 

[kerry]

It’s been about ten years. I think I ordered it from the dealer.

 

[glennm01]

Ah. When you said "I just bought a new one," I took it to mean you did this recently. Anyway, cool. I'll check with a dealer on Monday to see if a replacement is still available. Thanks.

 

[SkiFreak]

If the dealer says they can get it, ask them for the part number and then do a search online.
It is likely that you will get the switch cheaper that way.

 

[Aussie Iron]

A little bit of light grease will hold the springs and the plate in place and together while you try to reinsert it in it's place. But don't shake it while you have it upside down. What clips it together I don't know. One spring is twisted and the plate looks like it is melted on one edge. Pictures don't tell the whole story.

Dan.

 

[glennm01]

The plate isn't melted, there's a tab with a 90 degree bend that notches into a groove in the white cylinder. Here's a better angle:



The grease idea would probably work to get everything back in place, but the problem is there's nothing I can see that secures the knob in the dash hole at the right depth. Meaning you can easily just pull it back out. As a result, while the springs are supposed to ensure that the plate makes good electrical contact, they end up just pushing outward on the knob instead. Path of least resistance. There's gotta be some part I'm missing that's supposed to lock the knob at the right depth so the springs push the plate downward instead of pushing the knob outward. Ah well. I was hoping someone here might've dealt with this before, but it's looking like I'll either have to luck out and score a replacement, or trailblaze a DIY hack.

 

[Aussie Iron]

Okay, like I said pictures don't tell the whole story. And sorry, I'm not going to pull mine apart to see what holds it together. When you do find out please let us all know.

Dan.

 

[kerry]

The plate isn't melted, there's a tab with a 90 degree bend that notches into a groove in the white cylinder. Here's a better angle:

View attachment 691598

The grease idea would probably work to get everything back in place, but the problem is there's nothing I can see that secures the knob in the dash hole at the right depth. Meaning you can easily just pull it back out. As a result, while the springs are supposed to ensure that the plate makes good electrical contact, they end up just pushing outward on the knob instead. Path of least resistance. There's gotta be some part I'm missing that's supposed to lock the knob at the right depth so the springs push the plate downward instead of pushing the knob outward. Ah well. I was hoping someone here might've dealt with this before, but it's looking like I'll either have to luck out and score a replacement, or trailblaze a DIY hack.

My recollection is that the switch simply pushes in and pulls out.

 

[glennm01]

After investigating a bit more, I now think the switch that SkiFreak suggested above is in fact the right one. I had initially ruled it out due to the spade connectors shown in the photo, which are not present on what I had pulled out of my dash. I now see, however, that those connectors are part of a separate piece, which is actually what's still inside my dash. It looks like the part that I've circled in the photo below is what broke on my switch (actually there are a few of them, and they've all broken), and there are tabs there that *should* hold the two pieces together. After zooming in and comparing this to what I have, the only difference I see is the color, so at only $16, it seems well worth a try. Could be a couple weeks before I get it in, but I'll report back.

 

[glennm01]

There's a happy ending to this story folks, and on Thanksgiving no less. I finally got my hands on one of the Montero a/c knobs that SkiFreak linked to above, and sure enough, it is a match. Not quite *perfect*, mind you, as the Montero knob has 3 positions while my original Fuso knob only has two. Apparently the Montero has an additional "econo" mode that the Fuso does not have, but I suppose this is fitting -- there being nothing terribly economical about an '04 Fuso. But I digress. Fortunately, the Fuso only uses two of the blade connectors shown above, and they have continuity on both the econo and regular modes. So I now have off, on, and an additional mystery setting that will no doubt cause great consternation for the alien race that unearths my truck from its inevitable remote desert grave in a few hundred years. Then again, having conquered interstellar space travel, it may take a bit more than that to confuse them. Regardless, as I suspected, it was the band of plastic in the red circle above that failed. It extends all the way around the switch, and is what holds the two pieces together. Mine must've gotten brittle over time, because that whole band had broken off into pieces, leaving the bottom blade portion stuck inside the dash, while the knob was catapulted by its internal springs onto the seat. Mystery solved.

 

[SkiFreak]

Having another look at this switch, it could be possible to disassemble the new one and replace the internals from your original one, which should change it to a two position switch.
At only $15, I know that I would probably give that a go.

Should only take a small screwdriver to open up the switch.
Just remember that there are explody, springy things inside.