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Diagnosing Aircon Problems

StuH said:
What's the work in changing the condenser?
Click to expand...
gas needs to be removed before removing condenser.

when removing condenser it's a lot easier to remove the bumper first

I got an exact replacement condenser from Unipart for £70 and fitted it a few years back and it's still perfectly ok

I got Halfords to re-gas it. You might be able to get some place to remove and then replace the gas for you when you take the car back after replacing the condenser yourself. I thought there was no gas in the system on my car when I undid the pipes. For full story see #18 in http://typeaccord.co.uk/forum/topic/16996-air-con/
 
StuH said:
When driving down the Mway for several miles how cold should I start feeling the air? air con cold or just colder than it has been?
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The condenser is in front of the radiator, and there are two fans behind the radiator. One of those fans is an additional fan for the condenser, and both fans come on when the compressor is running. Those fans provide ample colling when the condenser is not perished, but when it gets badly perished, it eventually requires a howling gale to keep it cool.

The way it works is same as a fridge. The compressor compresses the gas to a liquid. The condenser keeps the liquid near to ambient temperature. The liquid pressure is released at the evaporator, which makes the evaporator cold. The gas returns to the compressor, etc, etc. There is a pressure switch in the system that stops the compressor from trying to compress too often.

The lower the ambient temperature (like today) the cooler the condenser will be. With a cool condenser, the evaporator has more chance of getting cold when the liquid pressure is released.

So the answer is, when driving at 60-70 mph, especially in cooler ambient temperatures, the more likely that the remains of the condenser will get the liquid closer to ambient, with a result that colder air will come off the surface of the evaporator.
 
I've not been on the mway just up the road but on Lo at level 4 its reasonably cool, not ice cool but cooler than outside temp.
 
the longer you drive at higher speeds, the colder it should get. But it does sound like a badly perished condenser

This is what the condenser looked like in my car before I removed it.
Click on the picture and the perished area (below the front cross beam) can be seen more clearly
I found out that there was still gas in the system, so perished condensers do not necessarily leak


0008.jpg



this is the condenser after removal, lying in the box that the new condenser was in (£70 from Unipart)

IMAG0128.jpg
 
That's certainly perished! Had a word with my mate who's a mobile mechanic, so long as I can get the gas removed he's happy to do the work. For the price of a new condenser and his labour it's a punt I'll probably take. Thanks for the advice.
 
Condenser on the way. I'm really surprised were Honda sites it, very vulnerable.
 
It's the standard place to put a condenser, but most other car companies put a mesh in front to protect it.

I don't know what the 8th gen is like, but the lower front grill is wide open to stones etc flying in. Look at other cars with a similar type of grill and the lower section has a mesh.

At least the condenser protects the radiator from damage.
 
Just an update;

Some might have seen my recent posting on another forum, if not I went back to the relay and fuse and cleaned them again. Amazingly, after doing this I had ice cold air! This lasted until lunch today, so about 24 hrs! I recently purchased an OBD2 scanner and today I used it for the first time, no codes came up. I had another look at the relay, taking it out and cleaning did nothing so I swapped it with the fan relay which resulted in ice cold air again! Strange thing is, when I swapped the back the air con was still working. I'm thinking the relay is starting to fail, that's what I hope anyway!
 
#85 "Took it down to Kwik-Fit for a gas, which they did, it made no difference so they didn't charge. The lad said pressure is fine, compressor is kicking in so it needs further investigation. "

#86 "***uming that Kwik-Fit are corect i.e. the gas pressure is correct and ***uming that the compressor is kicking in"

hmmm ..... rewind the tape :lol:
 
Just wanted to say thanks for the info in this guide and for taking the time to write it up. I've used it to diagnose my own A/C fault as being a duff clutch relay, which is rather pleasing as the weather is a little too warm to be without it at the moment. :)

Tom
 
What a useful thread! No cold air in my Accord over the last couple of months, and when I went for a re-gas, I was told the compressor wasn't working.

Followed the diagnosis steps at the start of this thread and it looks like I have a faulty relay as the click from the compressor was easily heard. There used ones on eBay but will look at mine first. I have a 12V power unit so can test the relay first.

Anyway, thanks to Brian for maintaining this topic over the last couple of years. It's sure to save people some money.
 
Awesome thread, just helped me find a fault :)

I fitted a new condenser yesterday and had it regassed earlier but the compressor wasn't kicking in, I thought I was looking at £££.

Did the relay test and it clunked, so I swapped the compressor relay for the fan one and it works, was blowing cold.

Obviously I won't use it with this faulty relay but what could happen if I did and the fan doesn't work?

How did you get the top off the relay, looks like a sealed unit? They are on ebay used for £7 so I'll buy one.
 
benw123 said:
Followed the diagnosis steps at the start of this thread and it looks like I have a faulty relay as the click from the compressor was easily heard. There used ones on eBay but will look at mine first. I have a 12V power unit so can test the relay first.
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Good work Ben



-Rich- said:
Did the relay test and it clunked, so I swapped the compressor relay for the fan one and it works, was blowing cold.

Obviously I won't use it with this faulty relay but what could happen if I did and the fan doesn't work?

How did you get the top off the relay, looks like a sealed unit? They are on ebay used for £7 so I'll buy one.
Click to expand...

Good work too Rich

I guess that the engine radiator might overheat in slow traffic due to the extra heat from the condenser in front, and not enough airflow to keep both radiator and condenser cool

btw I used a sharp tipped screwdriver to get the top off the relay: it's still working like that
 
Thanks Brian, that makes sense. With the aircon running the car has to work harder and you don't want it overheating by using just one fan. I guess there's a chance the compressor could overheat as well.

In hindsight I wish I'd checked these when it first stopped working. I checked the fuse but not the relays and with the condenser rotted I had ***umed there was no gas. When I removed the old condenser there was actually gas still in there although it still might not have been enough.

post-438-0-47528000-1406831397.jpg


So you've put the relay back in with no top, is that safe? I'll order another but will try cleaning the faulty one and maybe keep as a spare.
 
I can't see why it's not safe unless the engine bay fills up with petrol vapour while the aircon is running.

I think the amount of vapour has to be 1% which doesn't sound much, but apparently it's enough to make someone unconscious within a few minutes, so since the vapour would also be getting to the driver, I'd expect to have definitely stopped the car well before it reaches 1% in the engine bay. Maybe a safer thing to do on the diesel car LOL
 
Well I ordered the relay on ebay, should be here in a day or 2 and I'll open the old one up.

Could these checks be done on the Honda Civic as well, in the same way? I am replacing the condenser on ours but want to check the compressor clunks before calling someone out to find it doesn't work!
 
-Rich- said:
Could these checks be done on the Honda Civic as well, in the same way? I am replacing the condenser on ours but want to check the compressor clunks before calling someone out to find it doesn't work!
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I can't see any reason why not, indeed any car, they all have to have a relay to activate the compressor clutch
 
Cool, my main concern is where to put the wire - if it was put in the wrong hole could you damage anything?
 
Well there will be 4 holes: 2 for the relay coil; and 2 for the relay contacts.

You definitely don't want to be shoving a wire into either of the holes for the relay coil.

But as far as the relay contacts are concerned, it should not matter. One of the holes of this pair will be 12V +ve anyway, via a fuse. If you look through the pictures in #1 you'll see that I also do a test by bridging across the relay contact holes, and said that if the previous test (from battery +ve to one hole) worked but this other test does not, then the problem is the fuse.

Basically, when you remove the relay for the compressor clutch, you need to know which pair are the coil, and which pair are the contacts. If you have a test meter, you can tell which pair are the coil on the relay itself, because you can measure the reisitance of the coil on the relay, and the other pair will be open circuit (if both pairs are open circuit, then the coil is dead in the relay, but this would be extremely rare).

So just make sure you know which pair of holes are the relay contacts, then bridge across those, and if that doesn't work then the fuse must have gone, so try a wire from battery +ve into one hole then the other. If you still don't hear a clunk and you are definitely using the contact holes, then the fuse has gone and the compressor clutch is also open circuit, which would be strange and most unlikely.
 
I had my car re gassed last year and this year it wasn't cooling, checked pressure and it was low on gas again, refilled it and dyed and checked with uv but didn't find any leaks in the engine bay.

any ideas ? or maybe is how to access the evaporator behind the dashboard?
 
AFAIK the blower has to be removed to be able to examine the evaporator. To remove the blower you have to remove the glove box.
 
Thanks Brian found I had a faulty compressor clutch relay.
The one for a honda is expensive so I looked on Ebay and found a 5 pin 20a with no and nc contact it has the same pin configuration just an extra pin for the nc contact
the relay holder has 5 pin socket only 4 wired in the accord,but just to be sure I snipped off the extra pin total cost £3.10 yes £3 Ebay item 290881893044
Relay in and working.
great write up Brian thanks again
Jim
 
I have a 2004 Petrol 2 litre Accord. Up until 2 weeks ago the air con was working fine, since then it was intermittantly working where sometimes it worked perfect others it was blowing non chilled air. I got the system regassed and checked for leaks and none were found, thinking that was the problem but no improvement. I am trying now to diagnose whether it's the clutch that's on the way out or the compressor itself. When the problem first occured the system was working perfect blowing cooled air about 70/80% of the time, now it's lucky if it's 10%. I can see the clutch not spinning when it's not working and then when it is working I can see the clutch spinning. I tried swapping Relays initially but this has made no improvement and from my understanding of them they either work or it don't.

Any advice? It seems hard to source a new clutch online, also looking at this AC diagram I am wondering could it also be COIL SET, SOLENOID that is at fault or should I just go and get the full new compressor?
http://www.lingshondaparts.com/honda_car_parts_selection_pfk.php?block_01=17SEA01&block_02=B__5700&block_03=2840

Any help appreciated, thanks.
 
It's not entirely true that relays either work or don't. As relay contacts age they become "dirty", so that when the contacts close, sometimes they carry current, sometimes they don't carry current. But swapping the relays is a good test.

Do both fans run when the A/C is on ?
Did both fans run when you swapped the relays ?
Which relays did you swap ?


You can check the compressor with the engine running and A/C on by connecting a wire from the slot in the picture below, to the +ve terminal on the battery.

DSCF0744.jpg


but DO NOT LEAVE IT LIKE THIS FOR MORE THAN 30 SECONDS, DEFINITELY NO MORE THAN A MINUTE AT THE MOST, AND DO NOT REPEAT AGAIN FOR ANOTHER MINUTE. IF YOU LEAVE IT LIKE THIS WITH THE ENGINE RUNNING YOU MAY OVER PRESSURISE THE SYSTEM. (there is a safety pressure valve in the compressor, but do not rely on it operating)


The other source of the problem could be the pressure switch, the contacts in that might also be intermittent

DSCF0753.jpg


DSCF0754.jpg


again, DO NOT LEAVE IT LIKE THIS FOR MORE THAN 30 SECONDS, DEFINITELY NO MORE THAN A MINUTE AT THE MOST, AND DO NOT REPEAT AGAIN FOR ANOTHER MINUTE. IF YOU LEAVE IT LIKE THIS WITH THE ENGINE RUNNING YOU MAY OVER PRESSURISE THE SYSTEM. (there is a safety pressure valve in the compressor, but do not rely on it operating)



edit: when you do either test, also make sure that the temperature is set to "Lo"
 
So I need a new compressor it seems. Does the front subframe need dropping to replace it, and where can I get a compressor from?
 
I haven't replaced the compressor myself but I've seen a thread on here by someone who replaced it themselves. I can't find the thread but I'm sure that the subframe does not need to be touched, especially on the petrol-engined cars (much more room). If you want a new compressor try a Honda dealer, for 2nd-hand (used) a breakers or eBay.
 
This is excellent thanks brian, I will use this to sort my air con, it hasn't worked on my CL9 since ive had it, (no compressor start up). Will check fuses and relays first off.
 
The system in the petrol Accords is much simpler than in the diesel Accord, so it is fairly easy to trouble-shoot.

If you cannot hear the compressor coming on with the A/C temperature set to LO, switch off and check that the the compressor clutch pulls in using the wire trick (works with the key out of the ignition, but make sure you get it in the right slot). If it does pull in, try it again using the wire with the engine running (but make sure you don't leave it like that) and get an ***istant to feel if cold air is blowing. If cold air does blow, then the relay or pressure-switch is faulty, or worse still there's a break in continuity in the signal path from pressure-switch to the A/C controller (there's another thread on that).

If the compressor pulls in but no cold air, then it's either a perished condenser or the system needs re-gassing.
 
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