@ close to 200K miles, when the A/C clutch engages it sounds like Satan is having a seizure. So far what I glean from YouTube is that it may just be that the shim in the armature plate needs replacing with a different thickness. I'll try that tomorrow, but in the meantime has anyone else had this problem? The A/C does not need to be switched on. Is it normal for the clutch to engage with the A/C off? Thanks for any actual wisdom.

 

Screaming squealing is usually a slipping belt, as in not adjusted tight enough----- or maybe something in the accessory belt drive (a pulley) is trying to lock up
Now you're contradicting what you just said?

Only if the blower fan is on and one of the defrost positions is selected. Defroster position automatically enables the AC system by default No, that can't cause noise. Too much clearance would only cause the clutch to stop engaging

 

-.- now's your chance to perform an A/C delete. That useless mass of metal only leaches power and adds weight.

 

ezone, maybe you can illuminate this for me. I reassembled the clutch and tightened the serp belt and when I restarted the car, the clutch never tried to re-engage no matter what I did. I was not able to see if the problem was solved. What are the rules that dictate when the clutch engages? Since I needed to drive the car I just disconnected the field coil connector since I don't need A/C until next June anyway. I really like it that now when I start the car and select defrost, the cooling fans no longer run incessantly. I assume they do that to cool the condenser? At any rate, I have not yet grasped the logic behind how and under what conditions this system works and regulates itself. Next summer I'll reconnect the coil and see what happens. I may just D/C it every fall/winter/spring and give everything a break.

 

Oh, there's a lot going on.

The clutch has to be "right" and operable. That means correct clearance between plate and pulley (this is probably where yours is not correct??) , correct resistance of the field coil, and the coil is grounded. IF all this is correct, then the clutch should engage (CLICK) when 12v+ power is applied to the field coil through the center wire of the compressor harness plug, and the 12v+ comes from the compressor clutch relay.

The relay for the clutch has to be good, obviously, and it has to be controlled.

HVAC control panel creates a "AC request" signal that goes through the pressure switch, thermal protector, evap temp sensor, to the PCM. (If any of those interrupt the 'request' circuit, the pcm does not receive the request)
PCM has final say over whether the AC system should be enabled or not (engine overheating would disable the AC, for example).
If okay to run it, The PCM controls that clutch relay and it controls the radiator fan relays.

HVAC panel is set up to run the AC whenever defrost positions are selected, without the AC idiot light turning on.
The thermal protector on the compressor body must have continuity (the outer two wires of the compressor harness plug), or else the AC system is disabled. You disconnected it so the system is disabled, thus no fans until high radiator temperature dictates the need.


Absolutely.
Evaporator temp sensor. System makes the compressor run until the evaporator reaches just above freezing, then cycles the compressor off and on regularly to keep the evap core within a range of a few degrees.



Problem with leaving the compressor plug disconnected will be moisture entry and corrosion of the terminals, which will cause more problems later on.

I'd leave the compressor all connected clean and dry (watertight connectors) and disable it a different way. Up under the passengers side of the dash on the hvac case, unplug the gray 2 wire connector for the evap core temp sensor (close to the blower resistor).

 

It is really gratifying to get feedback from an authoritative source. I appreciate the warning regarding moisture in the connector. Would it also not work just to pull the A/C relay? Or would that cause another problem? Although not specifically named on the relay lid legend, I assume the one with the snowflake symbol only is the A/C relay? It is not specified in the owner's or shop manuals.

 

Even if you remove the compressor relay, you'd still have the radiator fans running whenever the system attempts to run the compressor (whenever it's set on a defroster position).

My idea was to interrupt the "ac request" circuit so the PCM doesn't attempt to turn it on.

Try this: Connect your compressor plug, start your engine and turn on the AC so the radiator fans are running (even though you said your compressor won't kick on now),
then reach under the dash and unplug the evap temp sensor and see if that shuts off the fans. (I don't have my GFs Fit here to try it)
I kinda assumed disconnecting the evaporator temp sensor would disable the AC system, but I'm not positive. Inquiring minds want to know now LOL

You could unplug the ac system pressure switch to disable the system, but I hesitate to do that because it would also be exposed to the elements which leads to corrosion problems. I'd rather unplug something inside the cabin because it's at least in a reasonably protected environment.
Yes
Dealer level info is where it's at, and even then sometimes it's not all that. It can be a real hair puller when you discover critical service information is missing or just flat out wrong

 

1) I put the OEM armature shim back on and then disconnected the connector you mentioned - white connector, gray wire jacket that connects to a red and blue wire. That did keep the a/c compressor clutch and fans from cycling on. 2) I decided to remove the new Continental serp belt and put the Honda one back on, to make sure it wasn't the belt. I reconnected the fitting. It was not belt slippage as the problem sounded worse. I put the Continental belt back on, cinched it up properly and then with the connector under the dash disconnected, the noise came back on intermittently from just the compressor pulley turning. So, I guess that's the problem. I can't avoid replacing the clutch assembly. Ordered it from Majestic. Thanks for the help.

 

So spin the compressor pulley and give it a wiggle by hand, is its bearing failing or bad? Noisy or too much free play?

Is the compressor locked up internally? (bypass using shorter belt?)

 

When I turn the compressor by turning the armature plate by hand, it feels fine, like I imagine a compressor feeling, some resistance but otherwise smooth. I can't feel anything weird in the pulley, but the shop manual does say replace the clutch if it is noisy. Should I remove the pulley and inspect it? It's just a snap ring.

 

Did you spin it by hand while the belt was off? A bad pulley bearing is usually pretty dang obviously noisy when you spin the pulley by hand, or feel excessively loose with side to side play when you grab and wiggle it.

You could stethoscope it before you take off the belt too, make sure it's not the alternator making noise or something. (long dowel or long screwdriver held to your ear works in a pinch)

Did you figure out why the clutch won't engage since you took it apart?? Incorrect clearance or bad field coil are expected.
Ohm test the coil, I'd expect it to be in the 3-4 ohm area.

AAAaaaand before you order stuff, make sure that compressor is original, not aftermarket. I've found out the hard way that factory parts usually don't fit aftermarket compressors.





When I picked up the 07 Fit for my GF, it already had 200k on it. I did a lot of work to it before I put her in it and the AC clutch/pulley and coil were among the many things I replaced.

 

The only time it was noisy until yesterday was when the a/c clutch was engaged. That is not a bad alternator, right? I bought the car new and know everything done to it. I'll pull the a/c clutch pulley today and report.

 

I just remembered at some point you had said it made noise without the compressor engaged.
You sure the belt is adjusted tight enough to not slip?

 

The belt is plenty tight, with the deflection specified by Honda. The pulley would only come half off the shaft, could not get it to come further without a puller. But when it spins freely it does have a bit of play, and does make some noise. The alternator pulleys, idler pulley and water pump pulley are all tight as a drum, silky smooth and silent when they spin. The compressor turns freely and feels silky smooth also, with the expected resistance because it is a compressor. I will borrow a puller from Auto Zone when the clutch kit comes. I assume I may as well replace the coil as well since I will have a new one. I'm thinking I'll wire a simple on-off switch into that gray connector spot and put the switch in the glove box. Then I can switch the A/C off and on as desired. Now I wait, because parts from Majestic take about a week to get to Alaska. Thanks for the help. Will report after surgical procedure is complete.

 

I put the new pulley and armature in and it was quiet until I included the compressor, and then it squealed, even a bit after I d/c the a/c. I finally decided to tighten the belt tighter than I ever had before, and w/o the a/c connected, the squeal is absent. I tightened the belt until I could not deflect it more than about 6mm max no matter how hard I pushed, and it was probably three additional whole turns on the 10 mm tightening nut. Since all is well and I don't need a/c until spring, I'm just going to leave it a mystery what will happen when I cut the a/c circuit back in. I guess it just made me skittish to tighten the belt that tight. I don't mind having a new idler pulley and especially don't mind a new a/c clutch kit since the OEM pulley had some play and made noise when it was spun. the new one is silky smooth, tight and silent.