Everytime I start my car and the AC is on there is a clicking noise coming from under the dash on the pass side. Ne one know what this may be?

 

The mode control motor probably

 

Everything works it just makes a clicking noise for about 20 seconds

 

what does it do if you turn the ac off when you stop the car?

 

ever changed the cabin filter?- its behind the glovebox- see diy section
could be all sorts of leaves and stuff in the fan blower area
use shop vac to remove

 

AC can be off but still clicks when car is started

 

Mine does this also. Time to replace my air mix motor. Does it whenever I go to full heat or cool. I guess the motor in it is bad. If I push the lever manually it works but if I don't it clicks trying to move but can't.

 

Mine only does it with the AC doesn't click of its over 80

 

It does it when trying to open or close the heater valve under the hood. Sounds like yours may be sticking when trying to close the valve. But its free when opening it.

 

Helpful info thanks guys

 

I have a '99 TL with 40k that just started doing this. The problem is a broken tooth on a plastic gear in the motor gearbox. I fixed it by taking apart the motor and turning the gear 180 degrees so the broken tooth doesn't mesh with the other gears.
You can only do this if the broken tooth is on the large main gear that's attached to the output shaft. It never makes a full revolution.

The motor is under the dash on the passenger side upper left, with a green connector.
Remove three 8mm screws (I had to unplug the middle ECU connector to get at the rear one)
Use a flat blade screwdriver to pry the plastic lever from the motor shaft.. take note of the position of the linkages.
The gearbox is held together with plastic clips. They're brittle.. I broke all but one, but it doesn't really matter - it goes together pretty tightly, and when you put the motor back in, the mounting screws will hold it together.
Carefully pry the gearbox halves apart, so the gears don't fall out.
Remove the circuit board on top of the large gear. If the broken tooth is on this gear, you can turn it 180 degrees and put it back in. There are 2 sets of 3 brushes that ride on the circuit board like a potentiometer for position feedback. They're exactly the same, so it doesn't matter if their position is reversed.

Everything was moving properly after I did this, but no heat - the heater valve cable was also broken under the hood right where it attaches to the valve. When I turned the lever on the heater valve manually, it was difficult at first, then loosened up. This could be what caused the problem in the first place.

 

My 01 CL is making this ticking/clicking noise when I turn climate control past 72, and no heat either. Could this be same issue?

 

Very likely. It's probably trying to open the mix door to let in some warmer air at 72 or above, but can't and makes the noise. Mine doesn't make a noise, but I get all cold air no matter what setting when my a/c is on - there's no mixing going on.

 

Check the cable under the hood near the firewall, it could be broken.. it's attached to a valve on a hose. You should see it move when you turn the temp up and down. See my previous post. Maybe this is a common problem

 

I ran the self-diagnosis function just for grins one day, and it indicated DTC 'K: a problem in the air mix control linkage, door, or motor'. I actually didn't realize I had a problem until then, but it made sense based on the constant cold air regardless of temp setting with a/c on. I'll have to check it out.

Unfortunately, all my wrenching time lately has been spent on my son's piece of sh!t Ford Escape. Transmission problems, misfire codes...grrrrr.

 

I've had the same problem, followed your instruction. I noted that the lever on the gear box would not move. After rotating the large gear and connecting the gear box back togeather the lever still will not move. Seems that pressure on the three small gears locks things up. Did your gear box lever spin after putting the assembly back togeather? Thanks

 

The gearbox assembly does not move "freely" after putting it back together. There will be a little resistance when tryinmg to move it because of the tiny motor inside the housing. If it is not working at all I suggest reopening it, making sure everything was put back together and then reinstall it. Also pay close attention to the two pins that go into the vent housing when reassembling, there are two seperate plastic arms the pins go back into. Also while you have it open re-grease the inside to ensure proper operation. I have a 99 TL with 222,xxx mile on it and I know it had the motor was the original. The grease was turning brown inside. When I opened mine up and pulled the two gears off to get to the big one, sure enough, there was one tooth missing causing the clicking. I roated it 180 degrees and it fixed the clicking. One thing to note, the "L" looking arm assembly is connected to the big gear that has to be rotated. Mine was on there pretty tight, I had to use a tiny screw driver to free it from the gear to rotate it. If all else fails and it still does not work go to a Honda dealership for the part or www.hondapartsunlimited.com. The part # is 79160-S0K-A01. If you need help let me know.

Bundy

 

No worries. I have the same clicking sound and it only happens when AC is on and the temp is in between the settings.... if you increase the temp or reduce the temp... it will stop.

 

I had the same exact issue with my 2007 Acura TL.. this was exactly what happened to me, clicking noise under steering wheel. I took the motor off, disassembled and sure enough a tooth gear was broken off. I turned the gear 180° like mentioned here, assembled everything back together and it went away. Thank you so much!!

Little tip, when taking off the big gear try to remember the position of it so that you can turn it around as close to 180° as you can get otherwise the motor and the linkage won't align under the steering wheel when you go to put it back together. Since I forgot where it was I had to take it apart and put it back together few times in order to get the positioning just right.

​​​​​​This part costs $70 plus tax at AutoZone,

can go take my gf out for dinner. Good luck to all!
​​​​