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05 Compressor clutch troubleshooting

422K views 397 replies 101 participants last post by  DearSir 
#1 ·
A/C stopped working some weeks ago, wife put up with it until now. A visible check shows that the compressor isn't spinning. I checked the pressure and got ~30 psi on the low side and about the same on the high side if I recall (didn't commit high side press. to memory). I just checked the clutch relay and the coil resistance was 145 ohms. I checked that there was voltage on one of the relay socket pins. Put a jumper across that open contact and nothing happened; I heard to clutch pulling in. Got under the car but didn't jack it up and looked/felt on the top side of the compressor. Found the clutch wire and see that it goes to a plug/recept. near the fan. I doubt that there is a problem with the connector but I'll check it. If it's not the connector I suspect the clutch is bad. I can turn the compressor by hand with not too much torque; the resistance is consistent and it turns 'kinda' smooth. Are there any other tests that can be done? I've read many posts and see that some owners have replaced the clutch and some replaced bearings too. However if it's truly failed I guess I'll just replace the compressor complete. I'm on a tight budget so I can't afford to pay >$1000 for the dealer or indy to fix it.
 
#2 ·
any luck with your diag? my comp isn't turning either. seems similar to yours. I can turn it by hand. feels like your description.

how did you check your refrig pressure? since the compressor isnt pumping, my low side just reads >100psi. figured it needed to be pumping to get a good reading?
 
#3 ·
I'm not sure what you have and haven't figured out.

The clutch itself is pretty simple: book specs the gap between the pulley and the pressure plate at .3 to .55 mm. The field coil resistance should be between 3.9 - 4.3 ohm, maybe more on a warm day. If those two things are good, the clutch is probably OK.

The fact that you can turn the compressor is a very good sign.

The 30psi on the low side (I assume the compressor is not running, given the nature of your post) is probably the problem. There's a leak and you are low on refrigerant (assuming I understand your information correctly). Charge up the system with one can and see what happens. The fact that you got a pressure reading means you at least have a way to check the low side pressure and hook a can up to it?

I'm not clear if you did hear a click when you jumped the relay. "Nothing happened" and you said something about the clutch pulling in, but it's not clear.

If it's low refrigerant, the pressure switch will be open. The switch should be on the high side line (smaller diameter refrigerant line) towards the rear of the engine compartment on the passenger side. Disconnect the connector from the switch. Pin 1 on the connector and switch is aligned with the plastic retaining tab of the connector. Pin 4 is opposite pin one. On the switch itself, ohm out pins 1 and 4. Open means low pressure (<28 psi). Closed means OK. On the connector side, you should have 5v between pin 1 and body ground. If you short pins 1 and 4, the compressor should kick on.

Bridging pins 1 and 2 on the compressor clutch relay circuit (pull out the relay and put in a jumper) should engage the clutch. If you do this with the engine running, you should see the compressor start to turn...don't run it long. This is the definitive test of the clutch itself as there is nothing else between the clutch and the control circuit from pin 2 of the relay box.

The FSM has troubleshooting guides for the clutch circuit, the pressure switch circuit, and the clutch itself. I'm not sure that this is a bad compressor. Make sure there's adequate refrigerant before doing anything else.

chumbie said:
A/C stopped working some weeks ago, wife put up with it until now. A visible check shows that the compressor isn't spinning. I checked the pressure and got ~30 psi on the low side and about the same on the high side if I recall (didn't commit high side press. to memory). I just checked the clutch relay and the coil resistance was 145 ohms. I checked that there was voltage on one of the relay socket pins. Put a jumper across that open contact and nothing happened; I heard to clutch pulling in. Got under the car but didn't jack it up and looked/felt on the top side of the compressor. Found the clutch wire and see that it goes to a plug/recept. near the fan. I doubt that there is a problem with the connector but I'll check it. If it's not the connector I suspect the clutch is bad. I can turn the compressor by hand with not too much torque; the resistance is consistent and it turns 'kinda' smooth. Are there any other tests that can be done? I've read many posts and see that some owners have replaced the clutch and some replaced bearings too. However if it's truly failed I guess I'll just replace the compressor complete. I'm on a tight budget so I can't afford to pay >$1000 for the dealer or indy to fix it.
 
#4 · (Edited)
how to check clutch relay?

shall36:

I pulled the clutch relay. getting the normally open OK: no continuity. but how do I test powered? put 12v DC straight from the car battery to the power leads 3&4 on the relay? if so, any diodes? +/- to 3or 4 matter? then check for relay continuity? the service manual says to check for continuity across pins 1&2 when pins 3&4 are powered. recommendations for doing this with it out?

how much amperage is the clutch pulling? if I try the jumper sockets 1&2 on the clutch relay location with the relay removed, any wire do OK? deal? thanks.

I think the 145ohms is the reading you get across the clutch RELAY coil (I did anyway). not sure this is what one needs to test though.

re pressure switch:
I got continuity (closed) across pins 1&4 of the pressure switch.
I got 5.9vdc from pin1 to gnd (7.0vdc with ignition ON).
 
#5 ·
I'll check the resistance between the relay contact and ground. If the coil is good I'll see the ~4 ohm reading. If it's open, I'll check from the connector at the fan to ground just to make sure the connector is open.
I should've been more specific. 30 psi was on the low side with the engine running but the compressor wasn't turning. When I jumped the relay contact (bridging pins 1 and 2) I heard NO clutch pulling in. Based on the schematic I found on the web, the power to the clutch comes from an 'always on' 12V source through that relay; there's nothing else in the circuit so jumping the low pressure switch would have no affect on the test. There was 12V on one side of the relay contact pins, so the clutch should've pulled in. I suppose I should try it again with the engine running; maybe there's not much of a 'click' or 'clunk' so a test to see if the compressor turns would be more positive.
I checked the relay's coil just to make sure there was continuity, that's all. It's not a sure-fire test of the relay's function. To check the relay, put power back on the coil and then put your ohmmeter back on the contact terminals. You should see zero ohms or something very close. Then remove power to make sure the contacts open - you'll see megohms or OL, depending on your meter.
 
#6 · (Edited)
checked voltages:
pin 4 to GND has 12v with ignition ON. 0v to GND with ignition OFF.
pin 1 to GND has 12v all the time.
I NEVER get voltage across pin 3&4 though!? should I in order to engage the clutch relay when turning on AC? I do hear some relay kicking in and the condensor&rad fans turn on. maybe problem#1? no voltage across pins 3&4 ever to engage clutch relay. where do I go from here?

power tested the relay with relay removed:
I powered the relay to the battery directly and the relay was clicking in. I got continuity. relay seems to be working but maybe never getting 12v across pins 3&4 to activate.

jump tested the clutch:
jumped pin sockets 1&2 using a wire and did not engage the compressor. I pulled the 1P plug to the compressor and I do get 12v to GND from it when I jumper the pins 1&2 on the relay socket. but I do not get any voltage when the relay is in place so the relay is not being energized it seems.

clutch clearance & coil test:
seem to have enough clearance as could get 0.54mm gap tool in all the way around. snug but OK it seems. I cannot get an impedence reading (just OL, open circuit) on the 1P into the compressor versus GND. so then I removed the connetor directly on the compressor and checked for continuity of both the ground wire at the comp and the lead wire from the 1P connector to the comp housing connector. that wir piece had continuity so was OK. so maybe open wire internal to the compressor or coil is damaged at the compressor causing an OL? problem #2?

sure seems weird to have 2 simultaneous issues:
1) clutch relay not getting engage signal
2) compressor not responding to 12v input signal. seems to have open internal wire or coil

also, it was my understanding that the low and high side pressure would more neutralize in the system with the comp off giving you a high reading on the low press side. so maybe 30 psi is way too low with comp off. I am getting >100psi on low side with my comp off. cant get it to turn on ever now.

PLEASE HELP! at this point I will be at the mercy of a dealer or shop.
 
#96 ·
I found this post to be quite helpful with my 09. What would have been even better would be a picture of the relay involved. The cryptic pictures on the fuse box cover are very little help.

My wife told me yesterday that the a/c wasn't working. So I did a quick search of the forum to see what I could learn.

Once I found the relay, I pulled it and found the 12 volts where it should be. I jumped the big pins together and heard the stator click. I turned off the power and measured about 5 ohms resistance on the stator so I felt that it was working ok. I then tried to check the high side cutout switch. What a pain. Buried under some stuff, I thought I got a good reading with the car off. I really needed some clip on test leads to check it with the power on.

So today, I tried to find a can of R134a, but being March, AA didn't have it in stock. I ended up at Wally World which had a selection to choose from. I didn't think I was going to need it, bu it never hurts to have it in stock at home.

Next stop was the Honda parts department to buy a relay. The parts guy says it"s an 09, it might be covered. Not the way my wife drives it, over 45k already. So we find the relay, it's 8 bucks out the door. If this isn't the problem, it's good to have a spare.

Get home, slap in the new relay, and the clutch engages and I've got cold air.

So tomorrow, back to the parts guy and pick up another one, because it's good to have a spare.

Thanks,
 
#7 ·
Just a few things; neither my relays nor the sockets have pin numbers on them but on my schematic the coil is pins 3 and 4 and the normally open contact is pins 1 and 2 with 1 being on the hot side. The best way to test the circuit would be to clamp the negative lead of your DVM to the compressor body and work your way down starting at pin 1 of the relay.

You mentioned that pin 4 had 12V always and pins 1 only when the ignition was on. That's just opposite of the schematic I have. Is your relay or the socket marked with pin numbers?
 
#8 ·
oops. I got it all reversed from walking from the garage to the PC. I edited and corrected in the above post. pin 1 has 12v all the time. pin 4 only when ignition ON. thanks.

I am referencing the 2005 service manual BTW. seems to align with what you are doing as well.

so..any idea why I would not ever get a voltage across pins 3-4 in order to activate the relay? or maybe I am getting something when the relay is plugged in and can't measure it.

seems like the jumper of pins 1-2 would have engaged the clutch. looks like the first culprit to address is the OL on the compressor stator. for me at this point means $$$ at a shop.:(
 
#9 ·
Is there a thermal cut off switch on the 05 oddy?

I ran into a similar problem on my VW Jetta. It has a temp sensor in the rad hose so if the engine is running hot for some reason it kills the a/c to save its self.

Besides the obvious and it sounds like you have the service manual, with the automatic controls it could be lots of stuff.

Also have you checked the sunlight sensor on the dash?
 
#10 ·
haven't checked everything and I do believe it has those sensors but I did put 12vdc straight to the compressor clutch coil (stator) via jumping the relay pins. I confirmed that I was getting 12vdc to the end of that wire connector just before the compressor and then that lead had continuity all the way to the compressor housing connecter (what a pain that was to get to pull off the lead on the compressor housing without pulling out the compressor). and I get on open circuit reading when trying to read impedence on the compressor coil/stator. seems like that may be the culprit. I'm sure a dealer will at least say clutch and stator or maybe even entire compressor. may try a local A/C guy first.

if I thought I could deal with all the erfrig issues evac/plugging/refill I'd try DIY with a new stator kit for $60.

then I also read where others had the exact same diag. dealer starts replacing the stator/coil and the compressor shaft breaks! they then have to buy an entire new compressor!

maybe I should just look into aftermarket compressors entirely...it already has 70k on it and we run the AC every day in S.FL.
 
#11 ·
Jerald, I had a long reply already typed and then saw your last post; you were way ahead of me. So about all I can say now is yesterday while at Advance Auto I got a price for a reman. compressor for ~$270.00. If I find that my clutch is shot I'll probably get a reman. from them or online. Advance's reman warranty was the same as for a new compressor.
 
#12 ·
chumbie
$270 sounds great! (plus vac/refill/etc of course)
you planning on DIY then?
if so, what is your plan for evacuating the refrig, keeping the lines sealed off while opened, vacuuming out and refill? will the new compressor already come with correct amount of oil? so just have to add x-pounds of r134a? or will you take it somewhere to vacuum out and refill after you replace the compressor?

tomorrow I plan on calling Honda dealer to price out (for kicks and giggles), call an import Indie shop for pricing, and a more local just regular car shop place for pricing. I am betting they all will want to just replace the whole compressor. less labor. if they get part prices anywhere similar to Advance then might as well.

I assume Benardi Parts is all Honda genuine? (not that that's better!)
compressor $450
clutch set $133
stator $59

I still havent ruled out trying the stator DIY. that's what I'd really like to do. but, I am concerned about the compressor shaft breaking as others have had happen. this is the wife+kids daily car. I cant drag this out too long either! and at some point (white towel), pay the man and get on with my life. I tried!! sometimes it works out, sometimes it doesnt. I've saved $000s over the years DIY but A/C work I do not care for.
 
#13 ·
Yeah I'll try the DIY route if it looks like the compressor is the only culprit. I'd consider the clutch 'stator' if I could find a good writeup and also assess the other compressor parts' condition.

I'd take the ody to have it evacuated and probably then take it to a buddy's house who owns a vacuum pump. He owes me a favor or two! Since the compressor turns I'm not concerned that it locked up and sent schrapnel through the system, so that's at least one concern I can eliminate. I would assume that most shaft failures were due to the compressor locking up, so it may well be a worthwhile repair in lieu of a complete replacement.
 
#14 ·
I found this exploded-view diagram of the compressor. There appears to be two wires out of the clutch stator. So there's a ground. I think I'll check to see if that wire is still connected to it's ground which I guess would be the engine block. It will not be easy; I've stuck my hand up and over the compressor and even if I jack the van up, it'll be tough.

I also see that there appears to be one connector on top of the stator and one at the end of one wire. I think that connector at the end of the wire is the one I see mounted to one of the fan housings.

Jerald, which of those connectors did you check - or did you check both?
 
#15 ·
I'll check back tomorrow. I have the shop manual which has a write-up on the stator. I could always post or send it to you or sometihng (unless you're a gamecock fan up in SC! haha). I think the trick is maybe the clutch is pressed on? and when they try to pull it, the flimsy shaft cracks off just at the end? I admit I have not yet read it all yet. maybe now I'll go do that. dont tempt me! I want to do it for $60!!! my comp turns by hand also. firm but moves OK. not spinning loose. not siezed. so probably OK.

also, I had most of the liners off today (pesky tabs and all) and the compressor is within working range OK but I didnt really try to determine all the angles for the mounts bolts and such so was wondering if anyone else had done the compressor DIY.

I do plan on keeping the Ody for at least another half-life so maybe spending some $ on the A/C comp won't be too bad (trying to let myself sleep better tonight!).
 
#16 ·
you have it correct:
use a mirror and flashlight to look around and on top of the comp to see while under the car with the under-liners off. the single hot lead from the relay box comes down beside the rad fan to a 1P connector. I went so far as to jump the 1&2 pins and got 12vdc vs GND there. the final lead connects from there to a direct connector on the comp housing. this one is a PIA to get off but I finally got it off to test that final wire for continuity. I had to get under the car with both arms up on top of the comp. one to push in the plug safety lock on the side facing the front of the car. the other hand to pull the plug/wires off. then I tested for continuity for both the lead back up to the connector next to the rad fan and the ground lead vs comp housing. both were good. so my comp must be getting the 12v to it when I jumper the 1&2 pins but it does not budge.
 
#17 ·
Ha! I am Clemson/USC neutral. I went to school in the next state north but have worked with both grads. Anyway, I'd like to see the writeup if you have the time.

About those tabs; I agree they're a PIA. Must be a Honda tool to easily release and remove them. I noticed that I'm missing a few too. That under-engine shield was hanging down and my wife must've plowed many an asphalt and concrete bump. It's seen better days.
 
#18 ·
LOL! oh good! unless you're a Tarheel! hahaha! just kidding of course.

the shield tabs are a pain. why not just use torx screws or something? I have to rememebr to order more next time I place a maint order from Benardi. but I also was referring to the connector on top of the compressor. if you are removing the comp anyway, just wait till you have it loose/off.

I see the Advance comp for $270!
also www.discountacparts.com has all these incl clutch:
reman $315
new $345
OEM $425
Benardi OEM was $445 incl clutch. if OEM it's probably reman too!
Advance is probably same quality as the reman above and no ship$. even if not in stock, probably get it for you next day.

I'll look at the write-up and see if it would be easier to type up or try to copy/email or something. I do receommend the shop manual. I got it for $70 online. not bad. it's great for all the tricks to the dash and interior stuff too (installed an ipod interface so had to pull the radio, etc) and it helped me through all this relay diag stuff.
 
#19 · (Edited)
chumbie:
made a few calls and reviewed the manual. doesnt seem bad at all. probably will need an A/C clutch removal tool (triangular; looks like a large watch tool). after the center bolt for pulley/clutch is removed there are some ring clips. the instructions said remove them and remove the clutch, then coil but it didnt say anything about pressing off so I wasn't sure about that? once the center bolt is off and the rings off, do the clutch and coil just easily slide off? or is something else needed to press them off? no mention in the book).

dealer: clutch & coil all inclusive with vac/recharge/etc $870+tax!
dealer: comp all inclusive $1270+tax!!

called a local shop guy: said my diag was exactly what he'd do in pulling the plug and putting a meter to the coil (like manual). if open ckt, then bad coil. said he might be able to pull it off without removing the compressor so as not to have to deal with the refrig refill costs! he also requires new dryer element if comp is replaced for warr on comp. I thought about trying to remove coil while mounted but the manual said remove the comp. however, I will look again tonight but I think it just might be do-able. originally, I was thinking I'd need to still unbolt the comp to move around but now thinking no. just leave bolted on. get the belt off, then get the pulley while mounted. with the wheel off and liners peeled back or off, the comp pulley is almost staring you in the face and there is working room in there from below. the trick may be getting that clutch tool and getting good firm hold on it and getting it off without damaging the comp shaft (was reading on some posts that dealers have damaged them but maybe they were siezed anyway?).

anyone know how to measure the A/C clutch plate health? neither the coil nor the clutch set is a returnable item to Benardi b/c electrical devices.

also, in case new comp needed, your thoughts on getting the right amount and type of compressor oil in an aftermarket (Advance) compressor DIY?
 
#20 ·
update:
taking to local Indie shop tonight for clutch coil only. part$ is Honda MSRP $80.32 and 2 hrs labor at $80/hr. he will try to do it without removing from AC lines to avoid refrig vac/recharge costs.

BTW, both my local Honda dealers are marking this part up to $102! 20% markup on part alone over Honda MSRP!!

sure hope this pans out well.
 
#21 · (Edited)
My diagnosis work was correct (thanks to help from this forum). I did take it to a local guy and he was indeed able to pull the AC clutch, pulley and coil off while the compressor was still mounted so as to avoid dealing with refrig vacuum/recharge, etc. 2 hours labor at $80/hr and $80 part. going to pick it up in just a bit. hope this helps others!

now we at least know this job CAN be done with the compressor mounted in the car.

And....I believe I have found a new shop for my Ody!
 
#23 ·
Jerald, I guess I'll get back under the Ody and test the clutch coil as you did. If it's an open circuit I think I'll call around to find an indy shop and do the same as you did. I'll get a shop manual as well since it looks like we'll keep the van for awhile.

Is it working well after one day?
 
#25 ·
Hummm guess I gave the wrong impression about doing this solo.

I tried to do this my self,,, couldn't get the clutch off the compressor,,, after buying the removal tool and worked for about three hours, I gave up. Took it over to a friends Honda Shop,, the main key is getting the car up on the lift. Take compressor off and turn it slightly down.

We tapped on the pulley until it finally came off. It wasn't easy but alot cheaper than re-charging the whole system. I think I paid the shop $130 labor. It can be done but it's a major pain in the driveway,,
 
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