2007 LX A/C clutch won't engage
 

OK so I checked all the fuses and relay is good. All the lights on the controls are working and the fans both come on. It worked Friday then yesterday I got in the car and no a/c. I've read about a Thermal Limiter may be the cause. Where is this? Can I jump it out to test it? What does it look like? I cannot find answers to these questions. Any help would be Great!! It is toooooooooo hot to drive with no a/c. lol

Re: 2007 LX A/C clutch won't engage
 

The fans would not come on if the thermal limiter was blown. Disconnect the 3 wire AC harness plug on top of the alternator and the fans should quit. Now plug it back in.

Since the fans are running when you try to run the AC, that tells me the problem is in the relay and clutch areas.

I tap on the clutch relay first, see if it starts working. (Bad contacts, replace relay with the updated version.)

If no, then I would pull the clutch relay, and use a simple test light to see if I find 2 powers and 2 grounds in the relays socket.
That tells me which of the 4 are the problem. Then diag from that point.

HTH

Re: 2007 LX A/C clutch won't engage
 

OK and where might that clutch relay be?

Re: 2007 LX A/C clutch won't engage
 

Ummmm.....

Just what did you check then?







I think the clutch relay is the one closest to fuse #5 in the pic. Look in your lid, it is labeled with nothing but a plain snowflake.
http://www.team-bhp.com/forum/attach...under-hood.png

HTH

Re: 2007 LX A/C clutch won't engage
 

I switched relays # 6 & 7

Re: 2007 LX A/C clutch won't engage
 

6 and 7 in the pic I just posted? Those aren't relays.

Re: 2007 LX A/C clutch won't engage
 

yes a plain snowflake with some type of electrical logo

Re: 2007 LX A/C clutch won't engage
 

and the one at the far left of that has a snowflake also with another type of snowflake in a square box.

Re: 2007 LX A/C clutch won't engage
 

That would be for the AC condensor fan.

The AC clutch relay is a plain snowflake by itself.


I checked a minute ago, I called it right. Clutch relay is closest to fuse #5 in that pic.

HTH

Re: 2007 LX A/C clutch won't engage
 

OK Great! Success!! I tapped on the relay and the a/c came on. I will pick one up tomorrow. Thank You Very much!! I'm in N.C. and it is real hot here. lol

Re: 2007 LX A/C clutch won't engage
 

Try to get the updated relay,
Honda part number is 39794-SDA-A05...
MSRP is $25.25


The original type relay has its share of issues, but is cheaper.

Re: 2007 LX A/C clutch won't engage
 

cool man thanx. now time to hit the sack. later.

Re: 2007 LX A/C clutch won't engage
 

Hello- I'm new to the forums. I have the same problem in my 2007 Civic. The clutch won't engage but both fans on the radiator turn on when I push the AC button. I've tapped on the relay with the single individual snowflake and that didn't help. I pulled the relay and using a voltmeter verified that two of the 4 sockets have 12+ volts of power. Does this mean for certain the relay is bad? I'm willing to buy another relay but hate to buy parts without knowing if indeed the relay is bad.

I've also been told I could jump the connection on top of the receiver/dryer and that would tell me if the pressure is low in the AC system but for the life of me I can't seem to find the receiver dryer. The engine bay in the 2007 civic is super cramped.

Re: 2007 LX A/C clutch won't engage
 

This says the system has enough freon to run.



Swap with an identical relay to test it.
If it works now, STOP--you are finished.
Ignore the rest of this reply.
Buy a relay and replace the bad one.
Enjoy the AC on the ride home.

No. You only checked HALF of the circuits involved. Can't condemn anything until after testing is complete.

You found 2 terminals with B+.
Turn the key on, turn the AC on.
Now connect your voltmeter to B+ post, and probe the other 2 terminals in the socket to see if they show any ground (meter will show 12v when you touch the probe to a ground). One is for the PCM control, the other is for the clutch field coil.

You can also jumper the 2 largest terminals in the socket to check the clutch operation. (Do NOT jumper the 2 smaller terminals, you may roast the PCM!)


Swap to test.

Don't worry about it, that isn't your problem right now. The system has enough freon to operate. The fans would not run if the freon was empty.


HTH

Re: 2007 LX A/C clutch won't engage
 

Okay here is an update. I swapped the relay with the the other relay that has the snowflake and fan blade on it. Nothing changed. I then took my voltmeter and held the negative to the neg battery terminal and probed the 4 holes with the positive. Only the left most hole registered and voltage.

I'm not sure what you mean by B+. Pardon my ignorannce. Is that the positive battery terminal?

Re: 2007 LX A/C clutch won't engage
 

Update #2

With the test probe grounded slot 1 and slot 3 has voltage. The other slots have no voltage.

With test probe on the positive battery terminal slot 4 has 13+ volts but slot 2 has nothing.

What does this tell me? I assume the relays are both fine since swapping them made no difference. I also assume since the fans both kicked on that I have ample pressure in the lines.

Re: 2007 LX A/C clutch won't engage
 

Exactly.

https://www.civicforums.com/forums/a...p;d=1342043933

Handy diagram, I like it.
Ok, 3 and 4 are for the coil of the relay, this is the control side.
These are the narrower of the blades on the relay.
A fuse supplies power to one of them, the PCM controls the ground to activate the coil (electromagnet) inside the relay.

1 and 2 are from the contacts of the relay. In this relay design, when the coil is energized the contacts close to complete a circuit, just like the light switch on a wall in the house. In this application, power is supplied from a fuse to one terminal of the pair, the other terminal goes to the load (AC clutch in this case.)


That said......
So there is no continuity through the electromagnetic coil circuit from the relay socket to (and including) the compressor clutch.


Examine that circuit:
Figure out where it is open circuit at:
There is one connector for the compressor on top of the alternator, it has 3 wires.
Right now I can't get on the Honda site to check wire diagrams, so here's my guess: The center wire is probably to the compressor clutch, the outer 2 are for the thermal limiter switch IIRC.
Ohm check the one for the clutch. Then move down the harness, check right at the compressor (I believe there is one more connector right at the clutch).

The clutch coil and pulley sets are available separately from the compressor, if need be.


HTH

Re: 2007 LX A/C clutch won't engage
 

excellent help. I really appreciate it. There is a connector with 3 wires on top of the alternator. All 3 are red. When you say own check the clutch do you mean checking resistance from one end if the switch to the other?
Should this be done with the engine running and ac on?

Re: 2007 LX A/C clutch won't engage
 

There is a connector with 3 wires on top of the alternator. All 3 are red.

That's it.


own check

I said OHM.
Symbol: %u03A9
Greek letter: Omega
Electronics: Resistance




the clutch do you mean checking resistance from one end if the switch to the other?

Sorry.

A good compressor clutch coil will have a resistance of 2-5 ohms (roughly). So you are looking for this measurement through the wiring. You could go directly to the clutch connector and check there if you want to (hell, it could just be unplugged), but I usually check at the most convenient places first.

Meter set to OHMs. Lowest scale, like 0-200 ohms if you have a choice. Whatever is closest to zero ohms.
One meter lead on the battery negative.
Probe with the other lead:

You could start at the relay socket terminal that had no reading before, but we already know it's the problem area and won't move the meter.

Move down the line:

Disconnect the 3 wire connector on top of the alternator.
Probe the half that goes toward the compressor.
Check each of the 3 terminals.
Do ANY of them give a reading?
(I guess no.)

Move down the line:
To the compressor itself, its connector (I'm guessing there's still 3 wires there too)
First, see if it was just unplugged. (Seen this before.)
Ok, unplug it and do the same exact checks as above. (NOT on the wires this time, check directly on the compressor components)
Any readings?


Should this be done with the engine running and ac on?

No. Everything OFF for resistance checking.



---------------------------------------------------
And Hondas site is still down. Dangit.




HTH

Re: 2007 LX A/C clutch won't engage
 

I disconnected the 3 wire switch on the alternator. I tested the resistance across all 6 leads (3 going to compressor and 3 going in opposite direction into a wire harness). I got nothing across any of the leads. I wanted to test resistance on the wires at the compressor however the engine was way too hot to stick my arm down far enough to reach it. That manifold would've burned the crap out of me. I will try again tomorrow after everything cools down and I can reach it.

What do you expect will happen? If I get a reading on any of the three wires does that mean I have a faulty wire or connector going from the alternator to the compressor?

Thanks again for walking me through this step by step. It's extremely helpful.

Re: 2007 LX A/C clutch won't engage
 

Damn, the ohm symbol didn't transfer to here.
Greek letter Omega:
http://a0.twimg.com/profile_images/983202845/omega.gif






disconnected the 3 wire switch on the alternator

I HOPE you disconnected a CONNECTOR, not a switch. Sorry, I'm very technical here, little things like this can make a huge difference.


across all 6 leads

I said check 3, not 6.
A very particular 3.
I don't care about anything else here.

Not important now.
NVM.
Results were as expected.


Next step is checking the component ON the compressor. Test at the terminal for the clutch coil itself. (NOT the wires on the cars harness)
As outlined previously.


If there is no wiring damage, I'd expect it needs a field coil for the clutch (complete clutch set).



HTH

Re: 2007 LX A/C clutch won't engage
 

So if there is no continuity, there is an open circuit in the clutch field coil, and it needs replaced? How often does this happen? That is what my '07 GX is doing, starting this afternoon while in Baker, CA (+115 deg). What a PITA! I finally pulled the lower connector apart and still got nothing.

Would you recommend changing the entire clutch assy? Honda sells the clutch assembly, but doesn't appaer to have the field coil set, and the field coil set don't have the clutch.

Re: 2007 LX A/C clutch won't engage
 

Guys, rally appreciate this discussion. I live in Germany and on the way back from Italy my A/C cutout so am following this diagnostic tree with great interest!

Re: 2007 LX A/C clutch won't engage
 

Yes, unless you think you can rewind the electromagnetic field coil yourself.

Only when it goes bad this way.
Duh.

Actually, it's just one of many things and ways that the system can break. Sh!t don't last forever.

Always at the worst possible times.

I live in the rust belt. The pulley doesn't always come off cleanly, so I always like to have it ready if it ends up being needed. I have even had the snout of the compressor snap off trying to remove the pulley and bearing. It doesn't always go by the book. Sh!t happens, deal with it.



Also: On earlier replies I said to check at the connector right on the compressor, but according to the wire diagram there may not be any. The only one shown in the diagram is on top of the alternator.
I don't have an 8th gen handy to look at at the moment.

Re: 2007 LX A/C clutch won't engage
 

Here's a picture. Thanks for the comments.....

Re: 2007 LX A/C clutch won't engage
 

Ok, if you can access that little bullet connector, test there. If open circuit, that coil is either bad, or its ground is bad (usually bolted to top of compressor, never seen one bad so far though).

Re: 2007 LX A/C clutch won't engage
 

Easy enough to separate one handed. Was fairly certain after checking the 3 prong connector above. It will get plugged back in after the new compressor with new coil and clutch is installed. No sense only changing the only the clutch/coil when the compressor already has used at least 1/2 of it's life. $350 for new parts including the receiver, and access to an evac pump, make that decision easy.

Re: 2007 LX A/C clutch won't engage
 

So there is nothing for me to test at the compressor. I've been trying to figure out how to get t plastic skid plate off from underneith the car to no avail.

Re: 2007 LX A/C clutch won't engage
 

Good luck.

Inferior quality aftermarket parts are a darn good reason for me to replace only the clutch and coil on an original compressor.

I can do the job without opening the system too.

Re: 2007 LX A/C clutch won't engage
 

You mean you can't undo the "dammit pins"?
http://www.driveaccord.net/forums/sh...ad.php?t=49488


This one is easy, a small screwdriver pops them apart
http://www.aandrmotorsport.com/direc...vePushPins.JPG


They also use pins without the 2 slots. These pliers make short work of them
http://www.restockit.com/images/Prod...um/KDT3729.jpg

Or, a small hook tool can dig under the center part and lift it
http://www.sirius-radio-satellite.co...IT-103_lrg.jpg



Or just break off the stuck pins (I break them all the time), then use zip ties to reattach or buy more pins.



HTH