Hot/cold door in my truck’s air conditioner

Topic

New Reply

My truck’s A/C is stuck on hot – the temperature control will set it on cold for a minute, then it’s back to hot.

Turns out there’s a small door in the A/C system that directs hot or cold air to the A/C vents, and it keeps getting stuck on the hot side.

I found out that there is a motor connected to this door that is controlled by the temperature knob on the A/C control panel — it is called the “actuator”.

The actuator was bad, so I bought another (US$40). But no matter what I did, I couldn’t get the new actuator installed. I figured it was out of alignment with the door, so I put a long screwdriver bit into the hole on the A/C box, and manually turned the door all the way to hot or cold (I wasn’t sure which, but I knew it was all the way in one direction or the other). I then ran the A/C for a few minutes to see if it would produce hot or cold air at the vents (it was hot). I then plugged in the new actuator and turned the temperature control all the way to the hottest setting, so that the actuator would be aligned with the door. However, even after doing all of that, I still couldn’t get the actuator installed.

Then it hit me: Why not just leave the screw driver bit in the hole, then when I want to adjust the temperature, I can reach behind the glove box and manually turn it!

Another thing hit me: Why in the world didn’t Ford just put a cable from the A/C door to the temperature control? Why put a motor which will eventually wear out, rather than a cable which will never wear out?

Group "L" (Linux Mint)
with Windows 10 running in a remote session on my file server

4 users thanked author for this post.

wavy, cyberSAR, Charlie, Myst

Reply | Quote

Replies

[Charlie]

That would be way too easy!  Ford wants you to have to come into their dealerships to get those “used to be so simple” things fixed.  And pay mass quantities of money to do it.

Edit:  At least with a truck you might have easier access to the problem.

Even astrophysicist Carl Sagan when speaking astronomically used Billions, not Trillions.

• This reply was modified 2 years, 2 months ago by Charlie.

Reply | Quote

Back very, very long ago when I could still crumple myself up under a dashboard they did actually use a cable. Then I remember it went to vacuum activated. Now I assume it’s electrical run by the computer system – but I ain’t even gonna look

Reply | Quote

I drive a 2010 Hyundai Tucson. The driver’s side back door lock was not functioning correctly. It would unlock (with the rest of the doors) with two clicks on the fob unlock button, but when all the other doors locked, it did not. I had to open the door and manually lock it.

The shop wanted $179 to diagnose the problem, to be dismissed if I had it fixed. The bill for the “fix” was $731 – it was connected t the computer.

That’s a 13 year-old car! Forget vacuum or cable. I suspect everything is now connected to the computer, including the flap controlling hot/cold in your case.

Reply | Quote

Stuff like that makes you not want to buy another Hyundai.

Group "L" (Linux Mint)
with Windows 10 running in a remote session on my file server

Reply | Quote

I don’t think that is common to only Hyundai. I suspect that is much more wide spread these days.

Reply | Quote

Another thing that is connected to the computer on modern cars (but doesn’t need to be) is the tire pressure sensors. I’ve heard that a hacker can actually hack your car through the tire pressure sensors.

With my old truck, there are no tire pressure sensors. Discount Tires sells a retro kit that installs in your tires, just like a factory install; but it isn’t connected through the car’s computers – there is no need for that, because it works just fine as an independent system. I’m probably going to get this when it’s time to get a set of tires.

Group "L" (Linux Mint)
with Windows 10 running in a remote session on my file server

Reply | Quote

MrJimPhelps wrote:

With my old truck, there are no tire pressure sensors. Discount Tires sells a retro kit that installs in your tires, just like a factory install; but it isn’t connected through the car’s computers – there is no need for that, because it works just fine as an independent system. I’m probably going to get this when it’s time to get a set of tires.

I bought and installed Tires Pressure Kit from AliExpress (~$20)

Tires and display are connected using BT.
Solar/USB-A charging.

1 user thanked author for this post.

MrJimPhelps

Reply | Quote

I know this is a bit off topic, but any solution appreciated- before I spend mega £/$ with agent! – I have a UK Honda Jazz 2017  EX I-VTEC CVT (Fit in in US?). The Auto Idle Stop (turns engine off at while waiting at red light). Except that it doesn’t       A warning pops up saying I have a battery problem – it’s fully charged.

Reply | Quote

MikeAL8, I have the successor to the US Fit (HR-V 2018) and I use a couple of HR-V fora occasionally when I have questions.

Just doing a search on Honda Jazz Forum and Honda Fit Forum gave me a number of relevant results: you might consider asking your question in those. Good luck!

Win 7 SP1 Home Premium 64-bit; Office 2010; Group B (SaS); Former 'Tech Weenie'

1 user thanked author for this post.

MikeAL8

Reply | Quote

MrJimPhelps wrote:

Another thing hit me: Why in the world didn’t Ford just put a cable from the A/C door to the temperature control? Why put a motor which will eventually wear out, rather than a cable which will never wear out?

They did, back in the day.

The air mixture cable you describe is present and functioning nicely in my 33 year old car from the same manufacturer. It is the original cable. The temp knob is a bit stiff to turn, especially when cold, but it still works. The car also has vacuum motors as @cyberSAR writes, for the flaps that enable the switch from Max A/C (recirculate) to vent and from vent to defrost. Those are the originals too, still working.

Motors could be used for a few reasons. It won’t let the knob get stiff to the driver like my cable setup (if the stiffness is in the air box, the motor will still conceal that from the driver, unless it is not strong enough to do what it needs to do), and the use of electrical signaling to control the flap position allows programmatic control via the car’s electronics. That is also why modern cars have throttle-by-wire, allowing the PCM to handle the throttle position. I’m glad to have a cable for that too (also the factory original). The clutch cable, though, is not the original.

Dell XPS 13/9310, i5-1135G7/16GB, KDE Neon 6.2
XPG Xenia 15, i7-9750H/32GB & GTX1660ti, Kubuntu 24.04
Acer Swift Go 14, i5-1335U/16GB, Kubuntu 24.04 (and Win 11)

Reply | Quote

MikeAL8 wrote:

The Auto Idle Stop (turns engine off at while waiting at red light). Except that it doesn’t

I, contrary to you, hate the Start-Stop function and installed an eliminator.

1 user thanked author for this post.

MikeAL8

Reply | Quote

Alex5723 wrote:

MikeAL8 wrote:

The Auto Idle Stop (turns engine off at while waiting at red light). Except that it doesn’t

I, contrary to you, hate the Start-Stop function and installed an eliminator.

It’s a petty annoyance that a bit of techs works once or twice a year ago and now never!
Not made any better by Honda (UK) Tech Serice saying “Take it to a Honda Dealer”.

Bring on Right to Repair for vehicles.

Reply | Quote

In case anyone wants to know how I finally fixed my A/C:

The internal door moves very easily. And I remembered that it would always move by itself to hot, not to cold. So I tried once again to install the actuator. I plugged it in and turned the temp control to hot. I then attempted to install the actuator. The rod on the actuator dropped right into the hole on the internal door! I snapped the actuator down onto the top of the air box. My temp control now works perfectly, whether I want hot or cold.

Group "L" (Linux Mint)
with Windows 10 running in a remote session on my file server

2 users thanked author for this post.

Charlie, Myst

Reply | Quote

@suew – Thanks for your advice.

@alex5723 – I’ve had a chat with my repairer (not a Honda agent!) “Oh they can be tricky to repair, the battery is special (aka expensive); do you really want Idle Stop?”

Probably not, diagnostics worse ($$$) than a PC repair, so I’ll put up with the warning!

@MrJimPhelps – Well done!

3 users thanked author for this post.

MrJimPhelps, Alex5723, SueW

Reply | Quote

Related to this topic is how Ford switched from wire cable controls for the vent control (defrost, floor , front, etc.) to vacuum vinyl tubing and a vacuum reservoir. One hole in any of the tubing or connections and the whole system stops working.

Hint: Look at the tubing in the engine compartment for cracks (aka holes) in the tubing. Engine heat makes the tubing brittle and easy to crack over time.

HTH, Dana:))

Reply | Quote

I well remember the vacuum tubing, which still is in lots of places in modern cars. Back in the 1980s I had a Chevrolet (I think), and it had a plastic vacuum line harness – approx six vacuum lines were connected/extended through the harness. The harness had a leak, which was causing problems with opening/closing the A/C vents. I went to the Chevrolet dealer, and they gave me some small individual connectors and said to bypass the harness. I did, and the problem went away.

I actually do have a vacuum leak on my truck – it causes the A/C to turn off whenever there is a big power draw on the engine (e.g. when I try to pass someone, when I go uphill). A mechanic told me that the way to track down the leak is to crank the engine, then get a can of starter fluid and start spraying small amounts on the vacuum lines. When the engine revs up, you have found the leak, because starter fluid got through the leak and into the engine!

Group "L" (Linux Mint)
with Windows 10 running in a remote session on my file server

Reply | Quote

MikeAL8 wrote:

“Oh they can be tricky to repair, the battery is special (aka expensive); do you really want Idle Stop?”

This could be as simple as replacing a burned fuse.

Reply | Quote

We had a phrase for this that goes way back – “Planned Obsolescence”! It applies to just about everything now and started with electric light bulbs.  They were lasting too long to suit the manufacturers.

Even astrophysicist Carl Sagan when speaking astronomically used Billions, not Trillions.

1 user thanked author for this post.

SueW

Reply | Quote

The Chevrolet Cobalt, which was current when GM went bankrupt, had extremely daunting procedures for replacing light bulbs.

Reply | Quote

extremely daunting procedures for replacing light bulbs

Could be one of the reasons they went bankrupt.

Group "L" (Linux Mint)
with Windows 10 running in a remote session on my file server

Reply | Quote