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Discussion Starter #1
Hey everybody, I’m new here and in a desperate spot. I have an issue(s) where the climate control motor is not blowing at full strength anymore (it will intermittently give the hurricane force circulation we all know and love) and the a/c system will not shut off no matter what the setting o the dash. Don’t know if these are related or not. Does anyone know if this is a firmware problem vs a component problem? If so where to begin? I have the abilities to fix anything mechanical, including soldering of electrical components, but before I go tearing my wife’s car up I’d like to confirm that if is not a software issue.
 

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The two issues might be connected but first I would look at the compressor relay. They have been known for the contacts sticking closed keeping clutch energized. As for the blower, If the blower speeds are changing but the air flow is weak, it could be as simple as a very dirty filter. If the speeds are not changing than it could be the power module that controls the motor speed.
 

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Discussion Starter #3
Thanks I’ll check that relay out. The cabin air filter was the first thing I checked. Unfortunately replacing it didn’t seem to help. I am embarrassingly not up to speed on terminology, so to eliminate any semantic error, could you specify what and where said power module is?
 

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Discussion Starter #5
2010. Can’t remember the trim level. It’s the middle one. Wheels, sunroof, 6-disc changer. No fog lights, nav, or any of the fancy stuff. 2wd.
 

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First, if you step thru the different fan speeds do you hear the fan change speeds. Next if the fan changes speeds, pull the filter out completely to see if you get a large increase in air flow.
 

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Discussion Starter #7
Yes, the fan still does vary in speed and flow rate with the control knob. What I found interesting is that with, or without the filter in the cradle, there is a significantly higher air flow when the air filter cradle is removed. When I first tried this, I removed the filter and cradle and noticed the increase in airflow and thought that I had just bought a replacement air filter that was too restrictive. For the sake of process of elimination I removed the filter and replaced the cradle to seal off the gap and the air flow was again reduced. I have also already checked the airways leading up to the filter for blockages but there are none to be found.
 

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Does the airflow change when on Inside Air vs Outside Air?
Something is restricting the incoming air to the filter, as you cleverly found out. Good job troubleshooting, so far.
Buffalo4
 

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Discussion Starter #9
Strangely no. I had expected that it would, but no dice. Thanks for the props too (seriously). I’m an engineering student and it’s good to know that it might be starting to pay off.
 

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It may help being an engineering student because you may have access to a DVM and clamp on DC digital ammeter. These will be very useful to check the fan motor and power transistor module. Typical problems with the fan motor are bearings and brushes. Bearings are easy, the fan cage should turn freely and noise free. Brush problems show up due to poor electrical contact with the commutator and symptoms might be the motor just doesn't turn or low speed under load. If you can check the voltage across the motor leads at full speed you should see 12+ volts and the motor current should be approximately 15 amps.
Here's a youtube vid for troublshooting the power transistor and fan motor. It for an Accord but the CRV is the same.


While getting to the power transistor module is easy in the Accord, the CRV is harder.
Here's a vid for removing the power transistor module. Note they call it a resistor but it's a transistor. It was a resistor network in olden days.
 

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Welcome to the forum! I highly recommend you get yourself a factory service manual. I got mine off eBay on a CD in pdf form for about $45. Your HVAC control panel has a built-in diagnostic function, which may lend clues to what is going on there, but you'll need that manual to run it. The manual has extensive troubleshooting for all systems on the car. Here's a link:

https://www.ebay.com/itm/2007-2008-2009-2010-2011-Honda-CR-V-Shop-Service-Repair-Manual-CD/141644642117?hash=item20faadb745:g:7~gAAOSwDuJWwdJZ

The manual is over 3,200 pages. Mine has easily paid for itself and then some. The HVAC system is covered in Section 21 and is 145 pages long. Good luck and keep us posted on how it goes.
 

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Discussion Starter #13
Thanks for that link too. I had one of those manuals for a Prelude I owned and it was amazing. Had I realized I could come by them so inexpensively I’d have bought one already. I was anticipating the 2nd mortgage they have historically been.
 

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I can relate! The paper set I got for my F250 was over $160 plus shipping. Used. Very used.
 

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Discussion Starter #15
Well finals are over and I have time again. I never thought I would ever be so disappointed that a relay was good but the AC relay checks out. I believe I forgot to mention that not only will the compressor kick in any time the car is running, the condenser fan kicks in: i.e. the car behaves as if the ac switch is on and the vents are running regardless of what the dash panel is set to. This is starting to smell a lot like a faulty control panel to me. Here’s my next question, with a bit of background so bear with me. In a 96 prelude I had, I had the ac go out on two separate dash units due to faulty soldering. When I discovered the problem, I reflows the soldier and my ac was working again. Has anyone ever heard of a problem like this on these later models, and/or could faulty soldering cause problems where the ac stays on all the time and the fan becomes anemic?
 

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The HVAC dash control panel has it's very own self diagnostic, but it requires a complex procedure to run it. Instructions and a large troubleshooting section are in the manual. It's always possible for a cold solder joint to make its presence known on any board in the car, but the boards use surface mount technology and scale, so be careful.
 

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Discussion Starter #17 (Edited)
Took it to the dealer because it’s oil change time, and maybe they could look at it. While they did find some things that were in desperate need of attention I am ashamed to say, (low coolant meant cold drive to and from work for the wife ?) either they didn’t really pay attention to the AC clutch acting up, or it behaved because it knew it was at the dealer.
At any rate, I’m sitting here in the car with the dash controls completely removed from the car and the clutch still engages at random- usually at about 10 seconds after startup. Since it’s dark now I also noticed that when it’s running the interior lights flicker until the ac clutch kicks in. Turns out the relays for the radiator fan, condenser fan, and fan control relays are all rapidly clicking on and off until the ac clutch kicks in.
Think I might have a gremlin.... this is a huge bummer.
 

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That sounds like it could be a weak battery, or a bad ground or battery cable. Check the harness connectors there too, as well as the ones in the dash. A single loose pin in one of those multi-pin connectors or a broken wire at the pin. Test the A/C clutch coil too and check those wires. I hate these gremlins. It's that snide look in their eyes. Beyond a certain point you really need that service manual to troubleshoot.
 

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Discussion Starter #19
Also, they always get out on the wing, and then get shy when you try to show someone else. Yeah, I’m afraid I am getting into manual territory. I’m about 98% certain that if I had a proper wiring diagram/schematic I could prob predict where I would find the issue. :\
 

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Silly question - do you have the system in defrost mode? If so, the a/c will run even thought the a/c light is not on. Air conditioners are also dehumidifiers, and dehumidified air clears a windshield of fog much faster than humid air.
 
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